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1 year ago

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There are 15 people in a party, including Hannah and Sarah. We divide the 15 people into 3 groups, where each group has 5 people

. What is the probability that Hannah and Sarah are in the same group?

2 answers:

creativ13 [48]1 year ago

8 0

Answer:

0,333

Step-by-step explanation:

by fractions

Sindrei [870]1 year ago

5 0

Answer:15/3

Step-by-step explanation:

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The U.S. Energy Information Administration (US EIA) reported that the average price for a gallon of regular gasoline is $2.94. T

Anit [1.1K]

Answer:

a) 25

b) 67

c) 97

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample. In this problem, $\sigma = 0.25$

(a) The desired margin of error is $0.10.

This is n when M = 0.1. So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.1 = 1.96*\frac{0.25}{\sqrt{n}}$

$0.1\sqrt{n} = 1.96*0.25$

$\sqrt{n} = \frac{19.6*0.25}{0.1}$

$(\sqrt{n})^{2} = (\frac{19.6*0.25}{0.1})^{2}$

$n = 24.01$

Rounding up to the nearest whole number, 25.

(b) The desired margin of error is $0.06.

This is n when M = 0.06. So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.06 = 1.96*\frac{0.25}{\sqrt{n}}$

$0.06\sqrt{n} = 1.96*0.25$

$\sqrt{n} = \frac{19.6*0.25}{0.06}$

$(\sqrt{n})^{2} = (\frac{19.6*0.25}{0.06})^{2}$

$n = 66.7$

Rounding up, 67

(c) The desired margin of error is $0.05.

This is n when M = 0.05. So

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.05 = 1.96*\frac{0.25}{\sqrt{n}}$

$0.05\sqrt{n} = 1.96*0.25$

$\sqrt{n} = \frac{19.6*0.25}{0.05}$

$(\sqrt{n})^{2} = (\frac{19.6*0.25}{0.05})^{2}$

$n = 96.04$

Rounding up, 97

8 0

1 year ago

Ronnie wants to lower his utility bills to save money on his monthly expenses. He discovers that if he replaces his water heater

Soloha48 [4]

Alright, lets get started.

Last year, Ronnie's utility expenses were = 1935.67 $

After switching to electric water heater to solar water heater, his yearly utility bills get reduced.

This year, Ronnie's utility expenses are = 862.40 $

So the difference on utility bills Ronnie saved = $1935.67 - 862.40$

so, difference Ronnie saved = 1073.27 $

So, the percentage of amount Ronnie saved = $\frac{1073.27}{1935.67} *100$

Percentage of amount Ronnie saved = 55.45 %

Hence, 55.45 % Ronnie save on his utlility bills by switching to a solar water heater. : Answer

Hope it will help :)

5 0

1 year ago

Read 2 more answers

Simon has a quarter, dime, nickel, and penny in his pocket. He wants to buy a snack at the canteen that costs 40¢. If he pulls o

ludmilkaskok [199]

Answer:

It would be a 3/4 chance that he will pull the right 4 coins.

Step-by-step explanation:

8 0

1 year ago

A turtle and a snail are 300 feet apart when they start moving towards each other. The turtle is moving at a speed of 5 feet per

choli [55]

Answer:

Step-by-step explanation:

velocity of turtle = 5 feet / min

velocity of snail = - 11 feet / min

By using the formula of relative velcoity

the velocity of turtle with respect to snail is

V' = velocity of turtle - velocity of snail

V' = 5 - (- 11)

V' = 16 feet / min

3 0

1 year ago

If sin(2x + 7) = cos(4x - 7)º, what is the value of x?

ella [17]

Answer:

x = 15°

Step-by-step explanation:

<u>We are given;</u>

sin(2x + 7) = cos(4x - 7)

We are required to solve for the value of x

We need to know that for complementary angles;

Sin θ = Cos (90-θ) where, θ and 90-θ are complementary angles.

Complementary angles are angles that add to 90°
Therefore;

(2x +7) + (4x - 7) = 90

6x = 90

x = 15°

Therefore, the value of x is 15°

6 0

2 years ago