Solving a word problem with three unknowns using a linear...
Rachel, Trey, and Deshaun sent a total of 98 text messages during the weekend. Trey sent 4 times as many messages as Deshaun. Rachel sent 10 fewer
messages than Deshaun. How many messages did they each send?
Number of text messages Rachel sent:
221
Х
?
​

Answer:

Step-by-step explanation:

Given the expression in rectangular coordinate as x²+y²−4x=0, in order to write the given expression in polar coordinates, we need to write the value of x and y as a function of (r, θ).

x = rcosθ and y = rsinθ.

Substituting the value of x and y in their polar form into the given expression we have;

x²+y²−4x=0

( rcosθ)²+( rsinθ)²-4( rcosθ) = 0

Expand the expressions in parenthesis

r²cos²θ+r²sin²θ-4rcosθ = 0

r²(cos²θ+sin²θ)-4rcosθ = 0

From trigonometry identity, cos²θ+sin²θ =1

The resulting equation becomes;

r²(1)-4rcosθ = 0

r²-4rcosθ = 0

Add 4rcosθ to both sides of the equation

r²-4rcosθ+4rcosθ = 0+4rcosθ

r² = 4rcosθ

Dividing both sides by r

r²/r = 4rcosθ/r

r = 4cosθ

Hence the correct equation in polar coordinates is r = 4cosθ

Answer:

7

Step-by-step explanation:

George should be 150 mm taller than Martha.

Since George's height is 1.75 meters and Martha's height is 160 centimeters.

So here we convert the meters to mm

So,

[tex]= 1.75\times 100\\\[/tex]

= 1750 mm

Now 160 cm to mm

So,

[tex]= 160\times 10[/tex]

= 1,600 mm

So, the difference should be

= 1,750 - 1,600

= 150 mm

Therefore, George should be 150 mm taller than Martha.

Learn more about height here: https://brainly.com/question/15810288

Answer:

the answer is a=b

Step-by-step explanation:

Answer:

The formula for the probability distribution is:

P(X = n) = q^(n - 1)p

= [0.2^(n - 1)]0.8

Step-by-step explanation:

This is a geometric probability distribution.

The probability of success p = 80% = 0.8

The probability of failure is q = 1 - p = 0.2

The formula is:

P(X = n) = q^(n - 1)p

= [0.2^(n - 1)]0.8

Answer:

B

Step-by-step explanation:

Option A:

1.50÷18≈0.0833

3.00÷36≈0.0833

4.50÷54≈0.0833

Option B:

0.75÷15=0.05

Option C:

2.20÷15=0.146

Answer:

1. 36, 49, 64, 81

The pattern is going up by squares.  

2. 1/162, 1/486, 1/1458

The pattern is 1/3n.

Step-by-step explanation:

1. Before the blank spaces started we were at 5^2, or 25.  Now, we have to find 6^2, 7^2, 8^2, and 9^2.  That would be 36, 49, 64, and 81. It goes up by squares.

2. As the pattern continues, each number in the sequence is multiplied by 1/3 create the next number in the sequence.

Answer:

0.033316

Step-by-step explanation:

We use the z score formula to solve for this question.

Since we are given the number of samples in the question, our z score formula is given as:

z = (x-μ)/ S.E

where x is the raw score

μ is the sample mean

S.E is the Standard error.

x is the raw score = 900

μ is the sample mean = Population mean = 947

Standard error =

This is calculated as Population standard deviation/ √No of samples

= 205/√64.

= 205/8

= 25.625

We proceed to calculate the z score

z = (x-μ)/ S.E

z = 900 - 947/25.625

= -1.83415

Using the z score table for normal distribution,

P(x≤ z) = P(z ≤ -1.83) = P(x ≤ 900)

P(x<900) = 0.033316

Therefore, the probability the mean of the sample is below 900 is 0.033316

Answer:

Your question lacks some parts attached below is the complete question

Answer : 2.66

Step-by-step explanation:

The expected number ( E ) can be calculated using the formula below

[tex]E = \frac{row total * column total }{gross total}[/tex]

since we are computing the number of subjects that would prefer Linux operating system and are also rated as exceptional

The row total to be used = 53 ( row total of exceptional )

The column total to be used  = 13 ( column total of Linux )

The gross total to be used = summation of row total of both exceptional and no-exceptional = 259

BACK TO THE EQUATION

E = [tex]\frac{53*13}{259}[/tex]  = 689 / 259

E = 2.6602 ≈ 2.66

Answer:

Step-by-step explanation:

Given that:

mean μ = 70

sample size = 25

sample mean = 73

standard deviation = 7

level of significance = 0.10

The null hypothesis and the alternative hypothesis can be computed as follows:

[tex]\mathtt{H_o : \mu = 70} \\ \\ \mathtt{H_1 : \mu > 70 }[/tex]

The z score for this statistics can be calculated by using the formula:

[tex]z = \dfrac{X- \mu}{\dfrac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \dfrac{73- 70}{\dfrac{7}{\sqrt{25}}}[/tex]

[tex]z = \dfrac{3}{\dfrac{7}{5}}[/tex]

[tex]z = \dfrac{3 \times 5}{{7}{}}[/tex]

z = 2.143

At level of significance of 0.10

degree of freedom = n -1

degree of freedom = 25 - 1

degree of freedom = 24

The p - value from the z score at   level of significance of 0.10 and degree of freedom of 24 is:

P - value = 1 - (Z < 2.143)

P - value =  1 - 0.9839

P - value =  0.0161

Decision Rule: since P value is lesser than the level of significance, we reject the null hypothesis.

Conclusion: We conclude that energy drink consumption increases heart rate.

Step-by-step explanation:

Exterior angle BOA = 250°

Interior angle BOA = 360°- 250° = 110°

Now,

(A) BDA = interior angle BOA / 2 = 55°( Property of circles)

(B) From the figure, we observe that AOBC is a cyclic quadrilateral (i.e. sum of opposite angles is 180°).

Therefore, BCA + BOA = 180°

BCA = 180° - 110° = 70°

Answer:

13

Step-by-step explanation:

(3 - 2i)(3 + 2i)

Expand

(9 + 6i - 6i - 4i^2)

Add

(9 - 4i^2)

Convert i^2

i^2 = ([tex]\sqrt{-1}[/tex])^2 = -1

(9 - 4(-1))

Add

(9 + 4)

= 13

Answer:

13.

Step-by-step explanation:

(3 - 2i)(3 + 2i)

= (3 * 3) + (-2i * 3) + (2i * 3) + (-2i * 2i)

= 9 - 6i + 6i - 4[tex]\sqrt{-1} ^{2}[/tex]

= 9 - 4(-1)

= 9 + 4

= 13

Hope this helps!

Answer:

8 times a number plus 7

Step-by-step explanation:

Let the number be f.

Simply, 8 f+7 is the expression.

Thank you!

-3-2g+6+4g

3+2g

hope it helps

Answer:

-2g + 18

Step-by-step explanation:

-3(2g - 6) + 4g

First we use distributive property.

-3 × 2g = -6g

-3 × -6 = 18

now we have

-6g + 18 + 4g

Now we combine the like terms

-6g + 4g = -2g

Finally we have

-2g + 18

and they are not like terms so we leave them and the equation is solved.

Answer:

4

Step-by-step explanation:

i distributed the -2 to what's in the parentheses. that equal 0. I then moved the 4 to the zero so that it becomes positive. I just assumed that you were ask for Y

Step-by-step explanation:

y-4=-2(x+3)....eq(1)

y- 4= -2x-6

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

subtituting equation 2 in equation 1

(-2x-2)-4=-2x-6

-2x-6=-2x-6

=0

Answer:

hello your question is incomplete below is the complete question

Find the minimum sample size n needed to estimate μ For the given values of​ c, σ​, and E. c=0.98​, σ=6.5​, and E=22 Assume that a preliminary sample has at least 30 members.

Answer : 48

Step-by-step explanation:

Given data:

E = 2.2,

std ( σ ) = 6.5

c ( level of confidence ) = 0.98

To find the minimum sample size

we have to first obtain the value of  [tex]Z_{a/2}[/tex]  

note : a can be found using this relation :

( 1 - a ) = 0.98 ----- equation 1

a = 1 - 0.98 = 0.02

hence:  a/2 = 0.01

This means that P( Z ≤ z ) = 0.99  the value of z can be found using the table of standard normal distribution. from the table the value of z = 2.33

P( Z ≤ 2.33 ) = 0.99

To obtain the sample size n

[tex]n = (\frac{std*z}{E} )^{2}[/tex]

n = [tex](\frac{6.5*2.33}{2.2} )^2[/tex] =  (6.88409)^2

Therefore n ≈ 48

Answer:

Step-by-step explanation:

Let the missing number be 'x'

⇒[tex] \mathsf{15 + 9 = x(5 + 3)}[/tex]

Distribute x through the parentheses

⇒[tex] \mathsf{15 + 9 = 5x + 3x}[/tex]

Swap the sides of the equation

⇒[tex] \mathsf{5x + 3x = 15 + 9}[/tex]

Add the numbers

⇒[tex] \mathsf{5x + 3x = 24}[/tex]

Collect like terms

⇒[tex] \mathsf{8x = 24}[/tex]

Divide both sides of the equation by 8

⇒[tex] \mathsf{ \frac{8x}{8} = \frac{24}{8} }[/tex]

Calculate

⇒[tex] \mathsf{x = 3}[/tex]

Hope I helped!

Best regards!

Answer:

y - 3 = -1/2(x - 1)

Step-by-step explanation:

Hey there!

Well point slope form is,

[tex]y - y_{1} = m(x - x_{1})[/tex]

We can use the point (1,3)

y - 3 = m(x - 1)

Now we need to find slope with the following formula,

[tex]\frac{y^2-y^1}{x^2-x^1}[/tex], we’ll use the points (1,3) and (5,1).

[tex]\frac{1-3}{5-1}[/tex]

-2/4

Slope or m = -1/2

y - 3 = -1/2(x - 1)

Hope this helps :)

Answer:

9/3 = 3x/3

3 = x

The spring stretches 9 inches with 3 kilograms of weight attached to it

Step-by-step explanation:

Substitute y = 9 into the equation y = 3x, or locate the answer on the graph:

y = 3x

9 = 3x.

Divide both sides of the equation by 3

Answer:The spring stretches 9 inches with 3 kilograms of weight attached to it.

Step-by-step explanation:

Substitute y = 9 into the equation y = 3x, or locate the answer on the graph:

y = 3x

9 = 3x.

Divide both sides of the equation by 3:

The spring stretches 9 inches with 3 kilograms of weight attached to it.

Answer:

8,13

Step-by-step explanation:

Look at the pattern :

0,1,1,2,3,5,...,...,21,34,55.

As you see the number in the pattern was made by the sum of 2 numbers behind it. Then, the blanks must be filled by :

So, the blanks must be filled by 8 and 13

Answer:

In the two blanks would be 8, 13.

The pattern is practically the Fibonacci Code.

Step-by-step explanation:

The Fibonacci Code is a mathematical sequencing in which you start with two numbers and add them together to make the third number, then you add the third number and the second number together.  Practically you keep adding each new sum and the number before it in the sequence to find the next new sum.

After 55 in this pattern, the pattern would go 89, 144, 233, 377, 610, 987,...

Answer:

8 home games and 10 away games

Step-by-step explanation:

Total home goals

= 8+5+9+8

= 30

Number of home games

= 30/3.75

= 8

Total away game goals

= 7+8+4+5

= 24

Number of away games

= 24/2.4

= 10

Answer:

i think it is 8 home and 10 away matches

Step-by-step explanation:

Answer:

z(s) is in the acceptance region. We accept H₀  we did not find a significantly difference in the performance of the two machines therefore we suggest not to buy a new machine

Step-by-step explanation:

We must evaluate the differences of the means of the two machines, to do so, we will assume a CI  of 95%, and as the interest is to find out if the new machine has better performance ( machine has a bigger efficiency or the new machine produces more units per unit of time than the old one) the test will be a one tail-test (to the left).

New machine

Sample mean                  x₁ =    25

Sample variance               s₁  = 27

Sample size                       n₁  = 45

Old machine

Sample mean                    x₂ =  23  

Sample variance               s₂  = 7,56

Sample size                       n₂  = 36

Test Hypothesis:

Null hypothesis                         H₀             x₂  -  x₁  = d = 0

Alternative hypothesis             Hₐ            x₂  -  x₁  <  0

CI = 90 %  ⇒  α =  10 %     α = 0,1      z(c) = - 1,28

To calculate z(s)

z(s)  =  ( x₂  -  x₁ ) / √s₁² / n₁  +  s₂² / n₂

s₁  = 27     ⇒    s₁²  =  729

n₁  = 45    ⇒   s₁² / n₁    = 16,2

s₂  = 7,56   ⇒    s₂²  = 57,15

n₂  = 36     ⇒    s₂² / n₂  =  1,5876

√s₁² / n₁  +  s₂² / n₂  =  √ 16,2  + 1.5876    = 4,2175

z(s) = (23 - 25 )/4,2175

z(s)  =  - 0,4742

Comparing z(s) and  z(c)

|z(s)| < | z(c)|  

z(s) is in the acceptance region. We accept H₀  we did not find a significantly difference in the performance of the two machines therefore we suggest not to buy a new machine

The very hight dispersion of values s₁ = 27 is evidence of frecuent values quite far from the mean

Answer:

option a

Step-by-step explanation:

give person above brainliest :)

Answer:

  25/4 square inches

Step-by-step explanation:

The area of a sector of a circle is given by the formula ...

  A = (1/2)r²θ

where r is the radius and θ is the central angle in radians.

For your sector, the area is ...

  A = (1/2)(5 in)²(1/2) = 25/4 in²

Correct question is ;

The grade appeal process at a university requires that a jury be structured by selecting eight individuals randomly from a pool of nine students and eleven faculty.​ (a) What is the probability of selecting a jury of all​ students? (b) What is the probability of selecting a jury of all​ faculty? (c) What is the probability of selecting a jury of six students and two ​faculty?

Answer:

A) 7.144 × 10^(-5)

B) 0.00131

C) 0.0367

Step-by-step explanation:

We are given;

Number of students = 9

Number of faculty members = 11

A) Now, the number of ways we can select eight students from 9 =

C(9, 8) = 9!/(8! × 1!) = 9

Also, number of ways of selecting 8 individuals out of the total of 20 = C(20,8) = 20!/(8! × 12!) = 125970

Thus, probability of selecting a jury of all​ students = 9/125970 = 7.144 × 10^(-5)

B) P(selecting a jury of all faculty) = (number of ways to choose 8 faculty out of 11 faculty)/(Total number of ways to choose 8 individuals out of 20 individuals) = [C(11,8)]/[C(20,8)] = (11!/(8! × 3!))/125970 = 0.00131

C) P(selecting a jury of six students and two faculty) = ((number of ways to choose 6 students out of 9 students) × (number of ways to choose 2 faculty out of 11 faculty))/(Total number of ways to choose 8 individuals out of 20 individuals) = [(C(9,6) × C(11,2)]/125970

This gives;

(84 × 55)/125970 = 0.0367

Answer:

The  equation is  [tex]r = \frac{4 }{ 1 + cos (\theta )}[/tex]

Step-by-step explanation:

From the equation we are told that

    The  Eccentricity: e = 1

    The  Directrix is   y = 4

Generally the polar equation for e =  1  and  y  =  + c is mathematically represented as

         [tex]r = \frac{e * c }{ 1 + ecos (\theta )}[/tex]

So

         [tex]r = \frac{1 * 4 }{ 1 + 1 * cos (\theta )}[/tex]

        [tex]r = \frac{4 }{ 1 + cos (\theta )}[/tex]

Answer:

[tex]1(x {}^{8} + x {}^{4} + 1)[/tex]

Step-by-step explanation:

[tex]x {}^{8} + {x}^{4} + 1 =1( x {}^{8} + x {}^{2} + 1)[/tex]

Hope this helps ;) ❤❤❤

Let me know if there is an error in my answer.

Answer:

Step-by-step explanation:

Two events A and B are said to be independent if the occurrence of one of the events does not affect the other occurring. For example, the event of tossing two coins is an independent event since they occur simultaneously. Two events are therefore independent if the following are true.

P(A|B) = P(A)

P(B|A) = P(B)

P(A and B) = P(A)P(B)

If A and B are independent events with P( A) = 0.35 and P( B) = 0.55,

then P( A| B) is a probability of A occurring provided that B has occurred. This is known as conditional probability for an independent event.

From the condition above for independent events, P(A|B) = P(A) and since P(A) =  0.35, hence P(A|B) =0.35