A class has three fewer girls than boys. If the ratio of girls to boys is four to five, how many students are there in the class?

Step-by-step explanation:

5r + 10 = 65

5r =65 - 10

r = 55/5

r = 11

Answer:

r=11

Step-by-step explanation:

you first have to work with the brackets and then group the like terms

5(r+2)=8+57

5r+10=65

5r/5=65-10

5r/5=55/5

r=11

I hope this helps

According to the typist claim, we build an hypothesis test, find the test statistic and the p-value relative to this test statistic, reaching a conclusion that:

The p-value of the test is 0.1333 > 0.05, which means that there is not enough evidence to reject the typist's claim.

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In an interview for a secretary position at the dealer, a typist claims a tying speed of 45 words per minute.

At the null hypothesis, we test if the mean is of at least 45, that is:

[tex]H_0: \mu \geq 45[/tex]

At the alternative hypothesis, we test if the mean is of less than 45, that is:

[tex]H_1: \mu < 45[/tex]

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The test statistic is:

We have the standard deviation for the sample, so the t-distribution is used to solve this question

[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.

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45 is tested at the null hypothesis:

This means that [tex]\mu = 45[/tex]

On the basis of 70 trials, she demonstrated an average speed of 43 words per minute with a standard deviation of 15 words per minute.

This means that [tex]n = 70, X = 43, s = 15[/tex]

Value of the test statistic:

[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]

[tex]t = \frac{43 - 45}{\frac{15}{\sqrt{70}}}[/tex]

[tex]t = -1.12[/tex]

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P-value of the test and decision:

The p-value of the test is found using a left-tailed test(test if the mean is less than a value), with 70 - 1 = 69 degrees of freedom and t = -1.12.

Using a t-distribution calculator, the p-value is of 0.1333.

The p-value of the test is 0.1333 > 0.05, which means that there is not enough evidence to reject the typist's claim.

A similar problem can be found at https://brainly.com/question/24241851

Answer:

1.-4,-1,1,6

2.by substituting the values given, we get

32-|15+8|

32-|23|

32-23=9

3.-15+7=8

4..27-(-12)=27+12=39

5.-6.05+(-2.1)

-6.05-2.1=-8.15

6.-3/4-(-2/5)

-3/4+2/5

=-7/20

7.-9(-12)

=108

8.(3.8)(-4.1)

-15.58

9.(-8x)(-2y)+(-3y)(z)

(16xy)+(-3zy)

(16xy)-(3zy)

10.by substituting the value given,we get

2.5*(-3.2)+5

-8+5

-3

so here are the answers,mark as brainliest if u find it useful

thank you

Answer:

[tex]f(x) = 3x - 5[/tex]

For a zero, f(x) = 0:

[tex]{ \tt{0 = 3x - 5}} \\ { \tt{x = \frac{5}{3} }}[/tex]

Answer: A

Therefore, the answer is A.

Answer:

B

Step-by-step explanation:

10k + 17 - 7j - 18 - 11k

-k - 7j - 1

Answer:

Last option

....... -0.4

Answer:

10t+2

Step-by-step explanation:

2-5t+8+5t-8

10t+2

Answer:

12/13

Step-by-step explanation:

we know this is a right triangle, and we know that the hypotenuse is the longest side. so we can already say that the hypotenuse of the triangle is DF or 78.

when you draw it out, you find that the shortest leg is 30 and the second is 72 and the hypotenuse is 78. we also know that cosine is adjacent/hypotenuse. once you draw the triangle and notice which side is adjacent to angle F, just fit it into the formula and you get:

cos F = 72/78

cos F = 12/13

Answer: Choice C. [tex]\frac{12}{13}[/tex]

Step-by-step explanation:

Answer:

-x² + 13x + 2

Step-by-step explanation:

you are on ambitious level, and you cannot answer that yourself ? that is trivial. truly. no hidden traps, just straight forward adding and simplifying. what is the problem, please ?

-7x² + 6x² = -x²

5x + 8x = 13x

-1 + 3 = 2

Answer:

3rd option

Step-by-step explanation:

Given

(- 7x² + 5x - 1) + (6x² + 8x + 3) ← remove parenthesis

= - 7x² + 5x - 1  + 6x² + 8x + 3 ← collect like terms

= - x² + 13x + 2

Answer:

1) X = 0

2) X = 0 or X = 1

Step-by-step explanation:

1)

[tex] \sqrt{6x} + 9 + 2 = 11 [/tex]

6x = 0 since root can only be = 0 if radicand is 0

X = 0

2)

[tex] \sqrt{x} - 3 + 3 = x[/tex]

[tex] \sqrt{x} = x[/tex]

X = x^2 ( We are squaring both sides to simplify)

x-x^2 = 0

x (1-x) = 0 (Factor the expression)

X = 0 or

1 -x = 0

X = 1

Answered by Gauthmath

Answer:

16 pi

Step-by-step explanation:

This is 1/4 of a circle so the area is 1/4 of the area of a circle

Area of a circle is pi r^2

so the area is 1/4 pi r^2

                       1/4 pi (8)^2

                       16 pi

Answer:

y = 1/2x + 5/2

Step-by-step explanation:

y = 1/2x + b

5 = 1/2(5) + b

5 = 5/2 + b

5/2 = b

Answer:

Min = -16; max = 0

Step-by-step explanation:

I plotted the inequalities for the constraints (see pic).

Sub in the coordinates of the vertices into the optimisation equation.

z = -(-4) + 5(-4) = -16

z = 0

z = -3 + 5(-1) = -8

Therefore, the max value of z is 0, and the min value is -16

hope it helps you mark me as a brilliant

Answer:

a)  [tex]P(A \cup B)=0.23[/tex]

b)  [tex]P(X)=0.87[/tex]

Step-by-step explanation:

From the question we are told that:

Probability of contacting disease 1 [tex]P(1)=0.11[/tex]

Probability of contacting disease 2 [tex]P(2)=0.16[/tex]

Probability of contacting both disease  [tex]P(1\& 2)=0.2[/tex]

a)

Generally the equation for a Random contact is mathematically given by

[tex]P(A \cup B)=P(1)+P(2)-P(A \cap B)[/tex]

[tex]P(A \cup B)=\frac{11}{100}+\frac{16}{100}-\frac{4}{100}[/tex]

[tex]P(A \cup B)=\frac{11+16-4}{100}[/tex]

[tex]P(A \cup B)=0.23[/tex]

b)

Generally the equation for Probability of contacting both after having contacted one is mathematically given by

[tex]P(X)=\frac{P(1\& 2)}{P(A \cup B)}[/tex]

Therefore

[tex]P(X)=\frac{0.2}{0.23}[/tex]

[tex]P(X)=0.87[/tex]

Answer:

slope is Δy/Δx =

-5/1 = -5

the B intercept is 4

y = -5x + 4

Step-by-step explanation:

Answer:

The top choice is the answer. a1=7; an= 3*a_(n-1)

Step-by-step explanation:

Begin by finding out what the terms are multiplied by. It is a geometric sequence so multiplication is involved.

Take the 3rd term (63) and divide it by the second term.

63/21 = 3

What this means is that each term in the sequence is multiplied by 3 to get to the next term.

The first term is 7

So the answer is an = 3* a_n-1

The answer must be the top one. See if it works.

a2 = 3*a_(2 -1 )

a2 = 3 * a1

a2 = 3 * 7

a2 = 21 which it does.

Answer:

the answer is 20m/s

Step-by-step explanation:

speed = distance/time which equals to speed = 800/40, so the answer is 20m/s

Answer:

20m /s

Step-by-step explanation:

Speed = [tex]\frac{Distance}{time}[/tex]

             [tex]= \frac{800}{40}=\frac{80}{4}= 20[/tex]

=====================================================

Explanation:

We can rewrite 5 as 5s^0, since s^0 = 1 where s is nonzero.

Think of 2s as 2s^1

With those ideas in mind, the original polynomial turns into 5s^0 + 2s^1

Sorting the terms so that the largest exponent is first gets us the standard form 2s^1 + 5s^0

The largest exponent is the degree, so the degree is 1.

Side note: This trick only works for single variable polynomials.

Answer:

Jack

Step-by-step explanation:

convert the fractions to decimals to determine the person that painted the larger part of the wall

5/8 = 0.625

7/12 = 0.583

the fraction Jack painted is larger.

Answer:

He ate 1/12 of the pizza

Step-by-step explanation:

Divide the pizza by 4 to get the share each friend got

1/4

Then Binli ate 1/3 of his share

1/4 * 1/3 = 1/12

He ate 1/12 of the pizza

Answer:

x= -1

Step-by-step explanation:

Since x= 5 is a vertical line, the unknown line would also be a vertical line with an equation of x=___ as they are parallel to each other.

Given that the line passes through (-1, 2), the equation of the line is x= -1.

Parallel lines have the same slope and will never meet.

The equation with exactly one solution is  3x + 5 = 2x - 6. Option D is correct.

To determine which equation has exactly one solution, we need to solve each equation and see if we end up with a unique value for 'x'.

4x – 4 + 2x = 6x - 4

Combine the x terms on the left side: 6x - 4 = 6x - 4

This equation is an identity and holds true for all values of x. It doesn't have a unique solution.

B. 2(4x + 5) = 8x + 10

Distribute the 2 on the left side: 8x + 10 = 8x + 10

Similar to the previous equation, this equation is also an identity and holds true for all values of x.

It doesn't have a unique solution.

4x - 8 = 4(x - 4)

Distribute the 4 on the right side: 4x - 8 = 4x - 16

Subtract 4x from both sides: -8 = -16

This equation is contradictory and has no solution.

3x + 5 = 2x - 6

Subtract 2x from both sides: x + 5 = -6

Subtract 5 from both sides: x = -11

This equation has a unique solution, x = -11.

So, the equation with exactly one solution is  3x + 5 = 2x - 6. Option D is correct.

To learn more on Equation click here:

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Answer: 1. 41.67years

2. £9.21

3. 7.75cm

Step-by-step explanation:

1. At a party, thirty people have an age of 30, forty have an age of 40 and fifty an age of fifty. What is their average age?

Total ages = (30 × 30) + (40 × 40) + (50 × 50) = 900 + 1600 + 2500 = 5000

Total number of people = 30 + 40 + 50 = 120

Average age = Total ages / Total number of people

= 5000/120

= 41.67 years

2. In a hardware shop, there are 30 spanners costing £6, 55 hacksaws costings £9 and 10 soldering irons costings £20. What is the average cost per item?

Total cost of items = (30 × £6) + (55 × £9) + (10 × £20) = £180 + £495 + £200 = £875

Total number of items = 30 + 55 + 10 = 95

Average cost per item = £875/95 = £9.21

3. Using this frequency table, find the average height of a turnip.

Height (to nearest cm)

6cm 7cm 8cm 9cm 10cm

Frequency: 3 8 12 4 1

Total height = (3 × 6cm) + (8 × 7cm) + (12 × 8cm) + (4 × 9cm) + (1 × 10cm) = 18cm + 57cm + 96cm + 36cm + 10cm = 217cm

Total number of turnips = 3 + 8 + 12 + 4 + 1 = 28

Average height = 217cm/28 = 7.75cm

Answer:

28.26 in ^2

Step-by-step explanation:

The diameter is 6 inches

The radius is 1/2 of the diameter

r = 1/d = 1/2(6) = 3 inches

A = pi r^2 = 3.14( 3)^2  = 3.14 (9) =28.26 in ^2

Answer:

75

Step-by-step explanation:

Answer:

Step-by-step explanation:

Supplementary angles add up to 180°.

The angle x, supplementary with 105°:

Step-by-step explanation:

Since there is a 45 and 90 degree angle, this is a 45-45-90 triangle. The legs are equal in a 45-45-90 ttiangle. The hypotenuse sqr root of 2 times more than the legs. So this means the hypotenuse measure is

[tex]18 \sqrt{2} [/tex]

So we can set up a equation.

[tex] {18}^{2} + {x}^{2} = ({18 \sqrt{2}) }^{2} [/tex]

[tex]x = 18[/tex]

So the missing side is 18

Answer:

D. All three chose a valid first step toward solving the equation.

Step-by-step explanation:

Aaron, Blaine, and Cruz are solving the equation 4/7 (7 − n) = −1. Aaron started his solution by multiplying both sides of the equation by 7/4 . Blaine started by using the distributive property to multiply 4/7 by both 7 and −n. Cruz started by dividing both sides of the equation by 4/7 .

Which of the following is true?

A. Blaine and Cruz made an error in picking their first steps.

B. Cruz made an error in picking his first step.

C. All three made an error because the right side equals -1.

D. All three chose a valid first step toward solving the equation.

Given:

4/7(7 - n) = -1

Aaron:

4/7(7 - n) = -1

Multiple both sides by 7/4

4/7(7 - n) * 7/4 = -1 * 7/4

7 - n = -7/4

- n = -7/4 - 7

- n = (-7-28)/4

- n = -35/4

n = 35/4

Blaine:

4/7(7 - n) = -1

4/7(7 - n) × 7 = -1 × 7

4(7 - n) = -7

28 - 4n = -7

-4n = -7 - 28

- 4n = - 35

n = -35/-4

n = 35/4

Cruz:

4/7(7 - n) = -1

Divide both sides by 4/7

4/7(7 - n) ÷ 4/7 = -1 ÷ 4/7

4/7(7 - n) × 7/4 = -1 × 7/4

7 - n = -7/4

- n = (-7-28)/4

- n = -35/4

n = 35/4

D. All three chose a valid first step toward solving the equation.

Answer:

D-All three chose a valid first step toward solving the equation.

Step-by-step explanation:

Hope I Helped