A certain family has a husband, wife, son, and daughter. All together they are 68 years old. The husband is 3 years older than the wife, and the son is 3 years older than the daughter. Four years ago, all together the family was 54 years old. How old is the husband now?

Answers

Answer 1

Answer:

32

Step-by-step explanation:

Everyone added together = 68

Four years ago, they were 68 -16 = 52

But the question told 54 years.

So there was a girl who was 2 years.

Girl = 2

Boy = 2 +3 = 5

Husband = 3 +w

Wife =w

3 +w +w + 5 + 2 = 68

10 + 2w = 68

2w = 58

w = 29

Wife = 29

Husband = 29 +3 =32

Husband = 32 years

Answer 2

Answer:

[tex]\large \boxed{\sf \bf \ \ 32 \ \ }[/tex]

Step-by-step explanation:

Hello, please consider the following.

We know that "All together they are 68 years old." and "Four years ago, all together the family was 54 years old."

If all the family was alive four years ago, it means that four years ago the sum of their ages was 68 - 4 - 4 - 4 - 4 because they are four members, so it gives 68 - 16 =52 which is different from 54, right ?

It means that we have the daughter in between, 54- 52 = 2, so the daughter's age is 2, and then the son's age is 5.

The husband is 3 years older than the wife. Let's note W the wife's age, we can write W + 3 + W + 5 + 2 = 68

2 W + 10 = 68

2 W = 68 - 10 = 58 so W = 29

and then the husband's age is 29 + 3 = 32.

And we can verify that 32 + 29 + 5 + 2 = 68, and four years ago, 28 + 25 + 1 + 0 = 54.

Hope this helps.

Do not hesitate if you need further explanation.

Thank you


Related Questions

4. Solve the system of equations. (6 points) Part I: Explain the steps you would take to solve the system by eliminating the x-terms. (1 point) Part II: Explain the steps you would take to solve the system by eliminating the y-terms. (2 points) Part III: Choose either of the methods described in parts I or II to solve the system of equations. Write your answer as an ordered pair. Show your work. (3 points)

Answers

Answer:

The system of equations you want to be solved is not given. I would however give an example with which the method of elimination will be shown, and can be used in solving problems of the nature.

Step-by-step explanation:

Consider the system of equations:

x + y = 7 ................................(1)

2x - y = 8 ..............................(2)

To eliminate x:

First multiply (1) by 2 to have

2x + 2y = 14 ...........................(3)

Next, subtract (2) from (3) to have

3y = 6

y = 6/3 = 2

To eliminate y:

Add (1) and (2) to have

3x = 15

x = 15/3 = 5

Therefore, (x, y) = (5, 2).

The image of (-4,6) reflected along the y-axis is
a. (4, -6)
b. (-4,-6)
c. (4, 6)
d. (-4, 6)

Answers

Answer:

C(4,6)

Step-by-step explanation:

the x turns into its opposite when reflected across y same thing for y when reflected across x

Answer:

c. (4, 6)

Step-by-step explanation:

The rule of an reflection about the y-axis is: [tex]A(x,y)\rightarrow A'(-x,y)[/tex]

Apply the rule to  point (-4, 6):

[tex]\frac{(-4,6)\rightarrow\boxed{(4,6)}}{(x,y)\rightarrow(-x,y)}[/tex]

Option C should be the correct answer.

The probability distribution of number of televisions per household in a small town is given below.

x 0 1 2 3
​P(x) ​ 0.05 0.15 0.25 0.55


a. Find the probability of randomly selecting a household that has one or two televisions.
b. Find probability of randomly selecting a household that has one or two televisions

Answers

Answer: 0.20

Step-by-step explanation:

The given probability distribution of number of televisions per household in a small town:

x          0       1     2      3

​P(x) ​ 0.05 0.15 0.25 0.55

To find : The probability of randomly selecting a household that has one or two televisions ( in both parts a. and b.).

The computations for this would be :

P( 1 or 2) = P(1)+P(2)

= 0.05+0.15

= 0.20

Hence, the required probability= 0.20

Answer:

Step-by-step explanation:

Find X using the Angle Sum Theorem

Answers

Answer:

x = 20°

Step-by-step explanation:

So when I learned it we called it the exterior angle theorem not the angle sum theorem but here goes.

Since exterior angle = 110 Degrees,

--> The Inner 2 angles's sum = 110 Degrees

so, 70 + 2x = 110

=> 2x = 40

x = 20

x = 20°

Hope this helps!

There are three commercial tax-preparation offices in City A. The local Better Business Bureau has been receiving some complaints that one of the offices does not understand tax law well enough to provide expert advice. The Better Business Bureau has decided to invest several hundred dollars in grant money to test the claim. It has selected four people at random and has asked that they allow each of the offices to prepare their taxes using the same information. The following data show the tax bills ($1,000s) as figured by each office. The following data show the tax bills as figured by each office. The data are also located in the CD-ROM file Tax-test.Return Office 1 Office 2 Office 31 4376.20 5100.10 4988.032 5678.45 6234.23 5489.233 2341.78 2242.60 2121.904 9875.33 10300.30 9845.605 7650.20 8002.90 7590.886 1324.80 1450.90 1356.89Required:Use the ANOVA procedure on your calculator for completely randomized designs to determine whether there is a significant difference in the mean taxes due on tax returns?

Answers

Answer:

I have not answer

plz follow me....

A television screen has a length to width ratio of 8 to 5 and a perimeter of 117 inches. What is the diagonal measure of the screen (to the nearest tenth of an inch)?

Answers

Answer:

[tex]D = 42.5\ inch[/tex]

Step-by-step explanation:

Given

[tex]L = Length[/tex] and [tex]W = Width[/tex]

[tex]L:W = 8: 5[/tex]

[tex]Perimeter = 117[/tex]

Required

Determine the Diagonal

First, the dimension of the screen has to be calculated;

Recall that; [tex]L:W = 8: 5[/tex]

Convert to division

[tex]\frac{L}{W} = \frac{8}{5}[/tex]

Multiply both sides by W

[tex]W * \frac{L}{W} = \frac{8}{5} * W[/tex]

[tex]L = \frac{8W}{5}[/tex]

The perimeter of a rectangle:

[tex]Perimeter = 2(L+W)[/tex]

Substitute [tex]L = \frac{8W}{5}[/tex]

[tex]Perimeter = 2(\frac{8W}{5}+W)[/tex]

Take LCM

[tex]Perimeter = 2(\frac{8W + 5W}{5})[/tex]

[tex]Perimeter = 2(\frac{13W}{5})[/tex]

Substitute 117 for Perimeter

[tex]117 = 2(\frac{13W}{5})[/tex]

[tex]117 = \frac{26W}{5}[/tex]

Multiply both sides by [tex]\frac{5}{26}[/tex]

[tex]\frac{5}{26} * 117 = \frac{26W}{5} * \frac{5}{26}[/tex]

[tex]\frac{5 * 117}{26} = W[/tex]

[tex]\frac{585}{26} = W[/tex]

[tex]22.5 = W[/tex]

[tex]W = 22.5[/tex]

Recall that

[tex]L = \frac{8W}{5}[/tex]

[tex]L = \frac{8 * 22.5}{5}[/tex]

[tex]L = \frac{180}{5}[/tex]

[tex]L = 36[/tex]

The diagonal of a rectangle is calculated using Pythagoras theorem as thus;

[tex]D = \sqrt{L^2 + W^2}[/tex]

Substitute values for L and W

[tex]D = \sqrt{36^2 + 22.5^2}[/tex]

[tex]D = \sqrt{1296 + 506.25}[/tex]

[tex]D = \sqrt{1802.25}[/tex]

[tex]D = \sqrt{1802.25}[/tex]

[tex]D = 42.4529150943[/tex]

[tex]D = 42.5\ inch[/tex] (Approximated)

The graph of y = −4x2 + 13x + 12 is shown below. What are the zeros of the function (as exact values), the y-intercept, and the maximum or minimum value of the function?

Answers

Answer:

zeros: -3/4, 4y-intercept: 12maximum: 22 9/16

Step-by-step explanation:

The graph tells you the zeros of the function are x=-3/4 and x=4.

The y-intercept is the constant in the function: 12.

The maximum is 22.5625 at x = 1.625.

Find the odds in favor and the odds against a randomly selected person from Country X, age 25 and over, with the stated amount of education. four years (or more) of college

Answers

Answer:

25 : 63 and 63 : 25

Step-by-step explanation:

This is a complete question

The table shows the educational attainment of the population of Country X, ages 25 and over. Use the data in the table, expressed in millions, to solve the problem. of 10 questions ge 1: Ages 25 and Over, in Miltions 4 Years igh College 4 Years High School (Less than College School Only 4years) Cor Moce) Total Male 29 19 25 89 Female 11 28 23 Total 2 57 42 50 [176 Find the odds in favor and the odds against a randomty selected person from Country X.age 25 and over, with the stated amount of education. four years (or more) of college 21:67, 67:21 63:88, 88:63 25:63, 63:25 25:88, 88:25

According to the question, the relevant data provided in the question for the solution is as follows

Four years or more of college

Number of students = 50

Total = 176 students

Number of students does not belong = 126

So odds in favor is

= 50 : 126

= 25 : 63

And automatically out against the favor is 63 : 25

A carpenter is making doors that are 20582058 millimeters tall. If the doors are too long they must be trimmed, and if they are too short they cannot be used. A sample of 1010 doors is made, and it is found that they have a mean of 20462046 millimeters with a standard deviation of 1515. Is there evidence at the 0.050.05 level that the doors are too short and unusable

Answers

Answer:

Z= 0.253

Z∝/2 = ± 1.96

Step-by-step explanation:

Formulate the null and alternative hypotheses as

H0 : u1= u2 against Ha : u1≠ u2 This is a two sided test

Here ∝= 0.005

For alpha by 2 for a two tailed test Z∝/2 = ± 1.96

Standard deviation = s= 15

n= 10

The test statistic used here is

Z = x- x`/ s/√n

Z= 2058- 2046 / 15 / √10

Z= 0.253

Since the calculated value of Z= 0.253 falls in the critical region we reject the null hypothesis.

There is  evidence at the 0.05 level that the doors are too short and unusable.

If 2y = 6 - 3x, find y when x = 0

Answers

Answer:

2y= 6-3x when x=0

2y= 6-3(0)

2y= 6-0

2y= 6

y= 6/2

y= 3

#i'm indonesian

#hope it helps.

Answer:

[tex] \boxed{y = 3}[/tex]

Step-by-step explanation:

Given, x = 0

[tex] \mathsf{2y = 6 - 3x}[/tex]

plug the value of x

⇒[tex] \mathsf{2y = 6 - 3 \times 0}[/tex]

Multiply the numbers

⇒[tex] \mathsf{2y = 6 - 0}[/tex]

Calculate the difference

⇒[tex] \mathsf{2y = 6}[/tex]

Divide both sides of the equation by 2

⇒[tex] \mathsf{ \frac{2y}{2} = \frac{6}{2} }[/tex]

Calculate

⇒[tex] \mathsf{y = 3}[/tex]

Hope I helped!

Best regards!

Listed below are the commissions earned ($000) last year by a sample of 15 sales representatives at Furniture Patch Inc.
$4.0 $6.0 $7.4 $10.6 $12.5 $13.6 $15.4 $15.8 $16.8
$17.4 $19.1 $22.3 $37.1 $43.2 $81.4
a. Determine the mean, median, and the standard deviation. (Round your answers to 2 decimal places.)
Mean $
Median $
Standard deviation $
b. Determine the coefficient of skewness using Pearson

Answers

Answer:

Mean= $21.5067

Median = $15.8

Standard deviation= $19.02

Coefficient of skewness= $0.8991

Step-by-step explanation:

Mean =( $4.0 +$6.0 +$7.4+ $10.6 +$12.5+ $13.6+ $15.4+ $15.8 +$16.8

+$17.4+ $19.1 +$22.3+ $37.1 +$43.2 +$81.4)/15

Mean =$ 322.6/15

Mean= $21.5067

Median= middle number

Median = $15.8

Variance=( ($4.0-.$21.5)²+( $6.0. -.$21.5)²+( $7.4 -.$21.5)²+( $10.6 -.$21.5)²+( $12.5 -.$21.5)²+( $13.6. -.$21.5)²+ ($15.4 -.$21.5)²+( $15.8 -.$21.5)²+ ( $16.8 -.$21.5)²+ ($17.4-.$21.5)² +($19.1 -.$21.5)²+ ($22.3 -.$21.5)²+ ($37.1 -.$21.5)²+ ($43.2-.$21.5)²+( $81.4-.$21.5)²)/15

Variance=$ 5424.79/15

Variance=$ 361.65

Standard deviation= √ variance

Standard deviation= √361.65

Standard deviation= $19.02

Coefficient of skewness

=3( mean-median)/standard deviation

= 3(21.5-15.8)/19.02

= 3(5.7)/19.02

= 17.1/19.02

Coefficient of skewness= 0.8991

If you use a 5/8 inch drill bit instead of a 3/16 that the project called for ,your hole will be too . by inches

Answers

5/8 - 3/16
= 10/16 - 3/16
= 7/16
Therefore the hole will too big by 7/16 of an inch.

A Prefeitura da Cidade Feliz doou um
terreno para a Comunidade Viver Bem
discutir projetos que deveriam ser
implantados no local. Após um planejamento
participativo, ficou acertado que 45% da área
total desse terreno serão destinados a uma
creche;
3%,
para banheiros públicos e 12%
para uma academia de ginástica comunitária.
A sobra da área, que é de 960m² será
utilizada para uma pequena praça com
parque de lazer. Qual é a área total ocupada
pela creche, banheiros públicos e academia
de ginástica comunitária?

Answers

Aqui temos a seguinte divisao de terreno:

creche + banheiros + academia = 45% + 3% + 12% = 60%

O que sobra: Fazendo a conta, 100 - 60 = 40, restará 40%

No enunciado informa que sobraram 960m².

Logo concluimos que 40% = 960m²

Sendo assim, regra de 3:

   m²                %

  960   --------   40

    X     --------   60

40X = 960 . 60

X = 57600/40

X = 1440

Logo 1440m² é destinado para: creche, banheiros públicos e academia

de ginástica comunitária.

O terreno tem um total de 1440 + 960 = 2400m²

para cada espaço - novamente diversas regra de 3:

→ creche = 45%

    m²                  %

  2400   --------   100

    X        --------    45

X = 108000/100 = 1080

 

→ banheiros públicos  = 3%

    m²                  %

  2400   --------   100

    X        --------    3

X = 7200/100 = 72

→ academia de ginástica comunitária = 12%

    m²                  %

  2400   --------   100

    X        --------    12

X = 28800/100 = 288

provando:

60% = 1440m²  (visto acima)

creche - 1080

banheiros - 72

academia - 288

1080 + 72 + 288 = 1440 (60%)

If x = -1 then how much is 2x - 1

a) 1
b) -3
c) -2​
hurry please need to turn in 10 min

Answers

Answer: -3

Step-by-step explanation: 2x = -2 then you subtract 1 from that which is the same as adding negative one so -2 - 1 or -2 + -1 = -3

Given a population with a mean of µ = 100 and a variance of σ2 = 1600, the central limit theorem applies when the sample size is n ≥ 25. A random sample of size n = 50 is obtained. • What are the mean and variance of the sampling distribution for the sample means? • What is the probability that ¯X > 110?

Answers

Answer:

The probability that the sample mean is more than 110 is 0.0384.

Step-by-step explanation:

According to the Central Limit Theorem if we have an unknown population with mean μ and standard deviation σ and appropriately huge random samples (n > 30) are selected from the population with replacement, then the sampling distribution of the sample mean will be approximately normally distributed.  

Then, the mean of the sampling distribution of sample mean is given by:

[tex]\mu_{\bar x}=\mu[/tex]

And the variance of the sampling distribution of sample mean is given by:

[tex]\sigma^{2}_{\bar x}=\frac{\sigma^{2}}{n}[/tex]

The information provided is:

[tex]n=50\\\\\mu=100\\\\\sigma^{2}=1600[/tex]

Since n = 50 > 30, the central limit theorem can be applied to approximate the sampling distribution of sample mean by the normal distribution.

The mean variance of the sampling distribution for the sample mean are:

[tex]\mu_{\bar x}=\mu=100\\\\\sigma^{2}_{\bar x}=\frac{\sigma^{2}}{n}=\frac{1600}{50}=32[/tex]

That is, [tex]\bar X\sim N(100, 32)[/tex].

Compute the probability that the sample mean is more than 110 as follows:

[tex]P(\bar X>110)=P(\frac{\bar X-\mu_{\bar x}}{\sigma_{\bar x}}>\frac{110-100}{\sqrt{32}})[/tex]

                   [tex]=P(Z>1.77)\\=1-P(Z<1.77)\\=1-0.96164\\=0.03836\\\approx 0.0384[/tex]

*Use a z-table.

Thus, the probability that the sample mean is more than 110 is 0.0384.

in this diagram, bac~edf. if the area of bac= 6 in.², what is the area of edf? PLZ HELP PLZ PLZ PLZ

Answers

Answer:

2.7 in²

Step-by-step explanation:

Area of ∆BAC : ∆Area of EDF = BC² : EF² (based on the area of similar triangles theorem)

Thus:

[tex] 6 in^2 : x in^2 = (3 in)^2 : (2 in)^2 [/tex]

[tex]\frac{6}{x} = \frac{3^2}{2^2}[/tex]

[tex]\frac{6}{x} = 2.25[/tex]

[tex]\frac{6}{x}*x = 2.25*x[/tex]

[tex]6 = 2.25x[/tex]

[tex]\frac{6}{2.25} = \frac{2.25x}{2.25}[/tex]

[tex]2.67 = x[/tex]

Area of ∆EDF = 2.7 in²

The product of a number and 3 is equal to 15 minutes twice the number, find the number.​

Answers

Answer:

The answer is 3

Step-by-step explanation:

Let the number to be found be x

The product of a number and 3 is written as

3 × x = 3x

15 minus twice the number is written as

15 - 2x

Now equate the two statements

That's

3x = 15 - 2x

Group like terms

3x + 2x = 15

5x = 15

Divide both sides by 5

the final answer is

x = 3

Hope this helps you

Find the domain and the range of the relation.
Find the domain of the relation. Select the correct choice below and fill in the answer box to
complete your choice.

O A. The domain is _
(Type your answer in interval notation.)
B. The domain is {_}
(Type an integer or a fraction. Use a comma to separate answers as needed.)
Find the range of the relation. Select the correct choice below and fill in the answer box to
complete your choice.
O A. The range is _
(Type an integer or a fraction. Use a comma to separate answers as needed.)
OB. The range is {_}

Answers

Answer:

1) the domain is all real numbers

2) the range is

[tex]y \geqslant 3[/tex]

At α = 0.001, is the overall model significant?Group of answer choicesNo, F* < FcThe test is inconclusive because 0.001 < p < 0.10Yes, F* < Fc, and p < 0.05.Yes, F* > Fc, and p < 0.001.Yes, F* > Fc, and p > 0.05.

Answers

Answer:

No, F* < Fc

Step-by-step explanation:

Significance level or alpha level is the probability of rejecting the null hypothesis when null hypothesis is true. It is considered as a probability of making a wrong decision. It is a statistical test which determines probability of type I  error. If the obtained probability is equal of less than critical probability value then reject the null hypothesis .

The hypotenuse of a right triangle is 5 inches long. One of the legs is 1 inch longer than the other. What is the length (in inches) of the longer leg?

Answers

Answer:  4  inches

Step-by-step explanation:

1. We gonna find the the length of the right triangle legs using Phitagor theorem.

c²=a²+b²  (1)   , where c is triangle's  hypotenuse

a and b are the triangle's  legs.

Let the leg a =x,    so leg b=x+1 inches

Now we can write the equation using (1)

25=x²+(x+1)²

25=x²+x²+2*x+1

2*x²+2*x-24=0     ( divide by 2 both sides of the equation)

x²+x-12=0

Find the discriminant D=1+12*4=49

√D=7

x1= (-1+7)/2=3     x2=(-1-7)/2=-4 - x2=-4 not possible so length of the leg can not be negative.

So the shorter leg a=x= 3 inches

The longer leg b=x+1=4 inches

Find x . Round to the nearest tenth of a degree.

Answers

Answer:

36.9°

Step-by-step explanation:

Sin x = 9/15 = 3/5

x = sin^-1 3/5

x= 36.87

x= 36.9° to nearest tenth

Solve for x: 3(x + 1)= -2(x - 1) + 6.

Answers

Answer:

x=1

Step-by-step explanation:

3(x + 1)= -2(x - 1) + 6.

Distribute

3x+3 = -2x+2+6

Combine like terms

3x+3 = -2x+8

Add 2x to each side

3x+3+2x = 8

5x+3 = 8

Subtract 3 from each side

5x =5

Divide by 5

x =1

Amira has 3/4 of a bag of cat food her cat eats 1/10 of a bag per week how many weeks will the food last

Answers

Answer: 15/2 or 7.5 weeks.

If t represents the number of weeks that pass, then the situation can be represented as
3/4 - (1/10)t = 0
because the initial amount is 3/4 and it is decreasing by 1/10 per week, and we are trying to find when the bag will be empty (0).

Solving this, (1/10)t=3/4 -> t=15/2.

Two balls are drawn in succession out of a box containing 5 red and 4 white balls. Find the probability that at least 1 ball was​ red, given that the first ball was (Upper A )Replaced before the second draw. (Upper B )Not replaced before the second draw. ​(A) Find the probability that at least 1 ball was​ red, given that the first ball was replaced before the second draw. StartFraction 24 Over 49 EndFraction ​(Simplify your answer. Type an integer or a​ fraction.) ​(B) Find the probability that at least 1 ball was​ red, given that the first ball was not replaced before the second draw.

Answers

Answer:

The answer is below

Step-by-step explanation:

The box contains 5 red and 4 white balls.

A) The probability that at least 1 ball was​ red = P(both are red) + P(first is red and second is white) + P(first is white second is red)

Given that the first ball was (Upper A )Replaced before the second draw:

P(both are red) = P(red) × P(red) = 5/9 × 5/9 = 25/81

P(first is red and second is white) = P(red) × P(white) = 5/9 × 4/9 = 20/81

P(first is white and second is red) = P(white) × P(red) = 4/9 × 5/9 = 20/81

The probability that at least 1 ball was​ red = 25/81 + 20/81 + 20/81 = 65/81

B) The probability that at least 1 ball was​ red = P(both are red) + P(first is red and second is white) + P(first is white second is red)

Given that the first ball was not Replaced before the second draw:

P(both are red) = P(red) × P(red) = 5/9 × 4/8 = 20/72 (since it was not replaced after the first draw the number of red ball remaining would be 4 and the total ball remaining would be 8)

P(first is red second is white) = P(red) × P(white) = 5/9 × 4/8 = 20/72

P(first is white and second is red) = P(white) × P(red) = 4/9 × 5/8 = 20/72

The probability that at least 1 ball was​ red = 20/72 + 20/72 + 20/72 = 60/72


The length of each side of a cubical wooden block is 16 inches. What is the volume of
the block

Answers

Hey there! I'm happy to help!

To find the volume of a cube, you simply take whatever the side length is and multiply it by itself 3 times, which is also known as cubing the number!

16×16×16=4096

You can also write it as 16³=4096

This is because the length is 16, the width is 16, and the height is 16, so you multiply them all together!

I hope that this helps! Have a wonderful day!

a is less than or equal to 10

Lmk

Answers

Answer:

[tex]a \leqslant 10[/tex]

Step-by-step explanation:

a is less than or equal to 10

less than: <

equal: =

less than or equal to: ≤

Hope this helps ;) ❤❤❤

hope it helps you

imp=draw dark shaded point in thqt line and point towards left

A sample of bacteria is decaying according to a half-life model. If the sample begins with 700 bacteria, and after 10 minutes there are 140 bacteria, after how many minutes will there be 40 bacteria remaining? Round your answer to the nearest whole number.

Answers

Answer:

18 minutes

Step-by-step explanation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is the time,

and T is the half life.

A = 140 when t = 10.  Solve for the half life:

140 = 700 (½)^(10 / T)

0.2 = ½^(10 / T)

log 0.2 = (10 / T) log 0.5

10 / T = 2.32

T = 4.31

When A = 40, t is:

40 = 700 (½)^(t / 4.31)

0.057 = ½^(t / 4.31)

log 0.057 = (t / 4.31) log 0.5

t / 4.31 = 4.13

t = 17.8

Rounded to the nearest whole number, it takes 18 minutes.

The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes.

What is an exponential function?

In mathematics, an exponential function is a relationship of the type y = ax, where x is an independent variable that spans the entire real number line and is expressed as the exponent of a positive number.

The half-life decay formula is given as,

N(t) = N₀ [tex](1/2)^{(t / T)}[/tex]

Where T is half-life while t is the time taken.

N₀ is the initial amount,

As per the given,

N(t) = 140 when t = 10.

140 = 700 [tex](1/2)^{(t / T)}[/tex]

Take log both sides,

log 0.2 = (10 / T) log 0.5

10 / T = 2.32

T = 4.31 minutes

Put N(t) = 40

40 = 700[tex](1/2)^{(t / 4.31)}[/tex]

Take log both sides,

log 0.057 = (t / 4.31) log 0.5

t / 4.31 = 4.13

t = 17.8 ≈ 18 minutes

Hence "The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes".

For more about exponential function,

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The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.966 grams and a standard deviation of 0.315 grams. Find the probability of randomly selecting a cigarette with 0.305 grams of nicotine or less.

Answers

Answer:

The  probability is  [tex]P(X \le 0.305 ) = 0.01795[/tex]

Step-by-step explanation:

From the question we are told that

      The population mean is  [tex]\mu = 0.966 \ grams[/tex]

       The standard deviation is  [tex]\sigma = 0.315 \ grams[/tex]

Given that the amounts of nicotine in a certain brand of cigarette are normally distributed

    Then the probability of randomly selecting a cigarette with 0.305 grams of nicotine or less is mathematically represented as

        [tex]P(X \le 0.305 ) = 1 - P(X > 0.305) = 1 - P(\frac{X - \mu }{\sigma } > \frac{0.305 - \mu }{\sigma } )[/tex]

Generally

              [tex]\frac{X - \mu }{\sigma } = Z (The \ standardized \ value \ of X )[/tex]

So  

      [tex]P(X \le 0.305 ) = 1 - P(X > 0.305) = 1 - P(Z > \frac{0.305 - 0.966 }{0.315} )[/tex]

      [tex]P(X \le 0.305 ) = 1 - P(X > 0.305) = 1 - P(Z >-2.0984 )[/tex]

From the z-table(reference calculator dot  net  ) value of   [tex]P(Z >-2.0984 ) =0.98205[/tex]

So  

     [tex]P(X \le 0.305 ) = 1 - P(X > 0.305) = 1 - 0.98205[/tex]

=>  [tex]P(X \le 0.305 ) = 1 - P(X > 0.305) = 0.01795[/tex]

=> [tex]P(X \le 0.305 ) = 0.01795[/tex]

Question 3: The gasoline gauge on a van initially read ⅛ full. When 15 gallons of gasoline were added to the tank, the gauge then read ¾ full. How many more gallons would be needed to fill the tank?

Answers

Answer:

hi

Step-by-step explanation:

Answer:

6

Step-by-step explanation:

3/4=6/8

6/8-1/8=5/8

So 5/8 of the tank is 15 gallons.  This means each 1/8 of a tank is 3 gallons.

The van is currently 6/8 full. We need to add another 2/8 to completely fill the tank.  

2x3=6

You’ll need 6 more gallons to fill the tank.

A parent increases a child’s monthly allowance by 20% each year. If the allowance is $8 per month now, in about how many years will it take to reach $20 per month? Use the equation 20 = 8(1.2)x to solve the problem. Round to the nearest year. 1 year 5 years 2 years 16 years

Answers

Answer:

6 years

Step-by-step explanation:

A parent increases a child’s monthly allowance by 20% each year. If the allowance is $8 per month now. This is an exponential function, An exponential function is given by:

[tex]y=ab^x[/tex]

Let x be the number of years and y be the allowance. The initial allowance is $8, this means at x = 0, y = 8

[tex]y=ab^x\\8=ab^0\\a=8[/tex]

Since it increases by 20% each year, i.e 100% + 20% = 1 + 0.2 = 1.2. This means that b = 1.2

Therefore:

[tex]y=ab^x\\y=8(1.2^x) \\[/tex]

To find the number of years will it take to reach $20 per month, we substitute y = 20 and find x

[tex]20=8(1.2)^x\\20/8=1.2^x\\1.2^x=2.5\\Taking \ natural\ log\ of \ both\ sides:\\ln(1.2^x)=ln2.5\\xln(1.2)=0.9163\\x=0.9163/ln(1.2)\\x=5.026[/tex]

x = 6 years to the nearest year

Answer:

5 years

Step-by-step explanation:444

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