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2 years ago

Which equation demonstrates the additive identity property?

Mathematics

1 answer:

kramer2 years ago

6 0

It's the first one (7+4i)+(7-4i)=14

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How to find base area

Olegator [25]

The base area is (pi)(r squared).

3 0

3 years ago

Read 2 more answers

The length of a rectangle is twice its width. The length is 4 1/2 feet. What is the area of the rectangle in square feet?

MA_775_DIABLO [31]

Answer:

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Step-by-step explanation:

8 0

2 years ago

The dwarves of the Grey Mountains wish to conduct a survey of their pick-axes in order to construct a 99% confidence interval ab

Dmitry_Shevchenko [17]

Answer:

The minimum sample size needed is 125.

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:

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

For this problem, we have that:

$\pi = 0.25$

99% confidence level

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

What minimum sample size would be necessary in order ensure a margin of error of 10 percentage points (or less) if they use the prior estimate that 25 percent of the pick-axes are in need of repair?

This minimum sample size is n.

n is found when $M = 0.1$

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

$0.1 = 2.575\sqrt{\frac{0.25*0.75}{n}}$

$0.1\sqrt{n} = 2.575{0.25*0.75}$

$\sqrt{n} = \frac{2.575{0.25*0.75}}{0.1}$

$(\sqrt{n})^{2} = (\frac{2.575{0.25*0.75}}{0.1})^{2}$

$n = 124.32$

Rounding up

The minimum sample size needed is 125.

5 0

3 years ago

What is x when y is 204?

mario62 [17]

Answer:

X =

Y = 204 =

Step-by-step explanation:

8 0

2 years ago

I need help with the first two please

lesantik [10]

Answer:

1. 45 minutes a day cycling

2.$1.55 on each cup of coffee a day

Step-by-step explanation:

1. You would figure up how much he jogs per week by multiplying 15 times 5 which would be 75 minutes and then from there you would subtract 75 from 300 and get 225 and divide 225 and 5 and end up with 45

2. You would multiply $.75 by 4 to figure up how much he spends on donuts which is $3 and then subtract 15.40 from 3 and get 12.40 and divide 12.40 by 8 since he goes twice a day and end up with 1.55

3 0

2 years ago