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3 years ago

The triangles below are similar. State the scale factor, first to second.

Mathematics

2 answers:

Mariana [72]3 years ago

6 0

Answer:

C... just got the answer.

Step-by-step explanation:

Mandarinka [93]3 years ago

4 0

I think is b I’m sorry if is wrong

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two business partners, Ellen and Bob, invested money in their business at a ratio of 3 to 7. Bob invested the greater amount. th

Shtirlitz [24]

Answer:

Ellen invested $60 and Bob invested $140

Step-by-step explanation:

let the two amounts invested by 3x and 7x

(notice 3x : 7x = 3 : 7 )

then 3x + 7x = 200

10x = 200

x = 20

then 3x = 3(20) = 60

and 7x = 7(20) = 140

60+140=200

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3 years ago

I participated in a math competition but I did not do very good. Does anybody have some tips?

Stells [14]

Study 5 times on the subject you are focusing on.

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3 years ago

Given the replacement set {0, 1, 2,3 4,}, solve 6x - 3=3

IrinaVladis [17]

Answer:

Step-by-step explanation:

6x - 3 =3

6x =3 +3

6x =6

x=6 :6

x=1

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3 years ago

What is the area of the trapezoid shown ?

Irina18 [472]

Answer:

A = 1/2 * (a + c) * h

A = 1/2 * (6 + (2 + 6 + 2)) * 6 = 48

5 0

3 years ago

An automobile manufacturer would like to know what proportion of its customers are not satisfied with the service provided by th

butalik [34]

Answer:

a) A sample size of 5615 is needed.

b) 0.012

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

99.5% confidence level

So $\alpha = 0.005$ , z is the value of Z that has a pvalue of $1 - \frac{0.005}{2} = 0.9975$ , so $Z = 2.81$ .

(a) Past studies suggest that this proportion will be about 0.2. Find the sample size needed if the margin of the error of the confidence interval is to be about 0.015.

This is n for which M = 0.015.

We have that $\pi = 0.2$

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.015 = 2.81\sqrt{\frac{0.2*0.8}{n}}$

$0.015\sqrt{n} = 2.81\sqrt{0.2*0.8}$

$\sqrt{n} = \frac{2.81\sqrt{0.2*0.8}}{0.015}$

$(\sqrt{n})^{2} = (\frac{2.81\sqrt{0.2*0.8}}{0.015})^{2}$

$n = 5615$

A sample size of 5615 is needed.

(b) Using the sample size above, when the sample is actually contacted, 12% of the sample say they are not satisfied. What is the margin of the error of the confidence interval?

Now $\pi = 0.12, n = 5615$ .

We have to find M.

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$M = 2.81\sqrt{\frac{0.12*0.88}{5615}}$

$M = 0.012$

7 0

3 years ago