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2 years ago

Shelly biked 21 miles in 4 hours. How long will it take Shelly to bike 63 miles?

2 answers:

5 0

In order to do this, you need to use the equation:
distance=rate x time

So if you want to find out how long it will take you plug 63 miles into the equation.

63 miles=Rate x Time

You want to find out how long so you need the rate.

You can find the rate from the first sentence.

21miles=Rate X 4 hours
Rate=21/4 miles per hour
Plug this into the original equation.

63=(21/4)(time)

Time=12 hours

Anna35 [415]2 years ago

3 0

You can set up a proportion. So we see that shelly biked 21 miles in 4 hours. $\frac{21}{4} * \frac{63}{x}$ . Now you can cross multiply and get 21x (21 * x) = 252 (63*4). Then use the division property of equality and divide both sides by 21 to get x = 12 hours. Therefore Shelly biked 63 miles in 12 hours. Hope this helps! :D. Feel free to ask more questions, or ask questions about my explanation.

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45 minus 4.5. Show work

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Let's do subtraction by first starting with the ones place and then the tenths place of the subtrahend.
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3 years ago

A person who is 5 feet tall is standing 88 feet from the base of a tree, and the tree casts a 96 foot shadow. the person's sha

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2 years ago

Use the fact that the mean of a geometric distribution is μ= 1 p and the variance is σ2= q p2. A daily number lottery chooses th

butalik [34]

Answer:

a). The mean = 1000

The variance = 999,000

The standard deviation = 999.4999

b). 1000 times , loss

Step-by-step explanation:

The mean of geometric distribution is given as , $\mu = \frac{1}{p}$

And the variance is given by, $\sigma ^2=\frac{q}{p^2}$

Given : $p=\frac{1}{1000}$

= 0.001

The formulae of mean and variance are :

$\mu = \frac{1}{p}$

$\sigma ^2=\frac{q}{p^2}$

$\sigma ^2=\frac{1-p}{p^2}$

a). Mean = $\mu = \frac{1}{p}$

= $\mu = \frac{1}{0.001}$

= 1000

Variance = $\sigma ^2=\frac{1-p}{p^2}$

= $\sigma ^2=\frac{1-0.001}{0.001^2}$

= 999,000

The standard deviation is determined by the root of the variance.

$\sigma = \sqrt{\sigma^2}$

= $\sqrt{999,000}$ = 999.4999

b). We expect to have play lottery 1000 times to win, because the mean in part (a) is 1000.

When we win the profit is 500 - 1 = 499

When we lose, the profit is -1

Expected value of the mean μ is the summation of a product of each of the possibility x with the probability P(x).

$\mu=\Sigma\ x\ P(x)= 499 \times 0.001+(-1) \times (1-0.001)$

= $ 0.50

Since the answer is negative, we are expected to make a loss.

4 0

2 years ago

Michmoo Computer Company sells computers and computer parts by mail. The company assures its customers that products are mailed

Anastaziya [24]

Answer: (60.858, 69.142)

Step-by-step explanation:

The formula to find the confidence interval for mean :

$\overline{x}\pm z_c\dfrac{\sigma}{\sqrt{n}}$ , where $\overline{x}$ is the sample mean , $\sigma$ is the population standard deviation , n is the sample size and $z_c$ is the two-tailed test value for z.

Let x represents the time taken to mail products for all orders received at the office of this company.

As per given , we have

Confidence level : 95%

n= 62

sample mean : $\overline{x}=65$ hours

Population standard deviation : $\sigma=18$ hours

z-value for 93% confidence interval: $z_c=1.8119$ [using z-value table]

Now, 93% confidence the mean time taken to mail products for all orders received at the office of this company :-

$65\pm (1.8119)\dfrac{18}{\sqrt{62}}\\\\ 65\pm4.142\\\\=(65-4.142,\ 65+4.142)\\\\= (60.858,\ 69.142)$

Thus , 93% confidence the mean time taken to mail products for all orders received at the office of this company : (60.858, 69.142)

8 0

3 years ago