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3 years ago

Adam is subtracting 708 – 10 mentally. He thinks

1 answer:

8 0

Adam is correct because when the hundreds and tens digit changes in 708, that means that the 7 and 0 will change into 6 and 9

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How long is the coastline of canada

netineya [11]

All you need to do is add 12383 and 113211 to get 125594

8 0

3 years ago

Does 23^-1 (mod 1000) exist? If yes solve it.

sweet [91]

Yes, 23 has an inverse mod 1000 because gcd(23, 1000) = 1 (i.e. they are coprime).

Let x be the inverse. Then x is such that

23x ≡ 1 (mod 1000)

Use the Euclidean algorithm to solve for x :

1000 = 43×23 + 11

23 = 2×11 + 1

→ 1 ≡ 23 - 2×11 (mod 1000)

→ 1 ≡ 23 - 2×(1000 - 43×23) (mod 1000)

→ 1 ≡ 23 - 2×1000 + 86×23 (mod 1000)

→ 1 ≡ 87×23 - 2×1000 ≡ 87×23 (mod 1000)

→ 23⁻¹ ≡ 87 (mod 1000)

3 0

3 years ago

Courtney is twice as old as Andre and three yoars older than Natalio Courtnoy is half Shar's ago Tho differenco between Shani's

Ghella [55]

Answer:

Andre's

Step-by-step explanation

I think its Andre. I apologize if it is not.

3 0

4 years ago

Sketch the images of abcd after each translation

WARRIOR [948]

Do you have a picture?

3 0

3 years ago

The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day.

valina [46]

Answer:

A sample of 179 is needed.

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:

$\alpha = \frac{1 - 0.85}{2} = 0.075$

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

That is z with a pvalue of $1 - 0.075 = 0.925$ , so Z = 1.44.

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.

A previous study found that for an average family the variance is 1.69 gallon?

This means that $\sigma = \sqrt{1.69} = 1.3$

If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?

A sample of n is needed, and n is found for M = 0.14. So

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

$0.14 = 1.44\frac{1.3}{\sqrt{n}}$

$0.14\sqrt{n} = 1.44*1.3$

$\sqrt{n} = \frac{1.44*1.3}{0.14}$

$(\sqrt{n})^2 = (\frac{1.44*1.3}{0.14})^2$

$n = 178.8$

Rounding up

A sample of 179 is needed.

7 0

3 years ago