Select the expression that represents the following statement multiply the difference of 5 and 2 by 7, and then add 6.

Sam and Liam raced each other up and then down the hill. Sam's average speed up the hill was 1 mph, and his average speed down w

Furkat [3]

Answer:

Sam's time was 1 hour and 6.66 minutes (or 1 and 1/9 hours)

Liam's time was was 1 hour

So in conclusion, Liam was faster

Step-by-step explanation:

We got Sam's time by 1/1 because Sam was walking 1 mph and the length to reach the top of the hill is 1 mile. So it would take Sam 1 hour to walk 1 mile. Walking down the hill Sam's speed was 9 mph. So the equation would be 1/9. So you would get 1/9. 1/9 of 60 is 6.66 repeating.

For Liam it is pretty simple. Since he is going up the hill at 2 mph and the length of the bottom of the hill to the top is 1 mile, it would be 30 minutes. Repeat this for the top to the bottom and in total it would be 1 hour.

Hope this helps

3 0

2 years ago

We would like to create a confidence interval.

Vlada [557]

Answer:

c.A 90% confidence level and a sample size of 300 subjects.

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 $1-\alpha$ , we have the confidence interval with a margin of error of:

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

In which

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

In this problem

The proportions are the same for all the options, so we are going to write our margins of error as functions of $\sqrt{\pi(1-\pi)}$

So

a.A 99% confidence level and a sample size of 50 subjects.

$n = 50$

99% confidence interval

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The margin of error is

$M = z\sqrt{\frac{\pi(1-\pi)}{n}} = \frac{2.575}{\sqrt{50}}\sqrt{\pi(1-\pi)} = 0.3642\sqrt{\pi(1-\pi)}$

b.A 90% confidence level and a sample size of 50 subjects.

$n = 50$

90% confidence interval

So $\alpha = 0.1$ , z is the value of Z that has a pvalue of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

The margin of error is

$M = z\sqrt{\frac{\pi(1-\pi)}{n}} = \frac{1.645}{\sqrt{50}}\sqrt{\pi(1-\pi)} = 0.2623\sqrt{\pi(1-\pi)}$

c.A 90% confidence level and a sample size of 300 subjects.

$n = 300$

90% confidence interval

So $\alpha = 0.1$ , z is the value of Z that has a pvalue of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

The margin of error is

$M = z\sqrt{\frac{\pi(1-\pi)}{n}} = \frac{1.645}{\sqrt{300}}\sqrt{\pi(1-\pi)} = 0.0950\sqrt{\pi(1-\pi)}$

This produces smallest margin of error.

d.A 99% confidence level and a sample size of 300 subjects.

$n = 300$

99% confidence interval

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The margin of error is

$M = z\sqrt{\frac{\pi(1-\pi)}{n}} = \frac{2.575}{\sqrt{300}}\sqrt{\pi(1-\pi)} = 0.1487\sqrt{\pi(1-\pi)}$

6 0

3 years ago

The two trapezoids shown below are similar . What is the length of x?

dangina [55]

The length of x is 3. Since the two trapezoids are similar. In the second trapezoid the top is half of 10. so it would be logical for x to be 3

7 0

3 years ago

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✎Question:Amirah is 4 years elder than Priya and Shirley is 2 years younger than Priya. If the sum of their ages is 47, find the

Gnom [1K]

Answer:

Priya's age = 15

Amirah's age = 19

Shirley's age = 13

Step-by-step explanation:

Let x be the age of Priya.

According to the question,

Amirah's age = x + 4

Shirley's age = x - 2

Their sum is 47.

So,

x + 4 + x + x - 2 = 47

3x + 2 = 47

3x = 47 - 2

3x = 45

x = 45/3

x = 15

So,

Priya's age = 15

Amirah's age = 15 + 4 = 19

Shirley's age = 15 - 2 = 13

7 0

3 years ago

Read 2 more answers

Help Me Help Me Help!!!!

lions [1.4K]

X=6 because
9-6=3

X=3 because
2•3=6

X=2 because
1.5 or 1 1/2 • 2 = 3

Not sure if this was what you needed or not!

3 0

3 years ago

Read 2 more answers