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Lubov Fominskaja [6]

3 years ago

8

A fish was swimming LaTeX: 2\frac{1}{2}2 1 2 feet below the water's surface at 1:00 p.M. Three hours later, the fish was at a de

pth that is LaTeX: 3\frac{1}{4}3 1 4feet below where it was at 1: 00 p.M. What rational number represents the position of the fish with respect to the water's surface at 4:00 p.M.?

1 answer:

marin [14]3 years ago

8 0

Answer:

$\frac{23}{4}$ feet

Step-by-step explanation:

The depth of the fish to the surface of water at 1:00 pm = 2 $\frac{1}{2}$ feet

= $\frac{5}{2}$ feet

The depth of the fish to its initial position at 4:00 pm = 3 $\frac{1}{4}$ feet

= $\frac{13}{4}$ feet

The position of the fish with respect to the water's surface at 4:00 pm = the depth of the fish to the surface of water at 1:00 pm + the depth of the fish to its initial position at 4:00 pm

= $\frac{5}{2}$ + $\frac{13}{4}$

= $\frac{10 + 13}{4}$

= $\frac{23}{4}$

The position of the fish with respect to the water's surface at 4:00 pm is $\frac{23}{4}$ feet.

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2 years ago

Can someone help me with this question!??

Gnesinka [82]

Im so sorry i need points but

4 0

3 years ago

Customers arrive at a movie theater at the advertised movie time only to find that they have to sit through several previews and

Naddika [18.5K]

Answer:

Using a 90% confidence level

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Step-by-step explanation:

I think there was a small typing mistake and the confidence level was left out. I will use a 90% confidence level.

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

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Now, find the margin of error M as such

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In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

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We have the standard deviation in minutes, so the margin of error should be in minutes.

72 seconds is 72/60 = 1.2 minutes.

So we need a sample size of n, and n is found when M = 1.2. We have that $\sigma = 6$ . So

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Rounding up.

A sample size of 68 should be used.

B. If we want to estimate the population mean time for previews at movie theaters with a margin of error of 1 minute, what sample size should be used?

Same logic as above, just use M = 1.

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

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$(\sqrt{n})^{2} = (6*1.645)^2$

$n = 97.42$

Rounding up

A sample size of 98 should be used.

3 0

3 years ago

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Sav [38]

Answer:

Hey there!

I would prefer method two.

Both methods give the right solution, but method two is more straightforward. Instead of distributing, you simply divide and don't need to do as much work.

Let me know if this helps :)

7 0

3 years ago