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2 years ago

A set of headphones takes 5 minutes to charge up to 3 hours play. What is the unit rate?

Mathematics

1 answer:

Burka [1]2 years ago

4 0

Answer:

1.666667 headphones per hour (simplify this)

Step-by-step explanation:

divide the top and bottom by 3 and you should get your answer

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Lia must work at least 5 hours per week in her family’s restaurant for $8 per hour. She also does yard work for $12 per hour. Li

vladimir2022 [97]

As the question states, let r be the number of hours worked at the restaurant, and y be the number of hours of yard work.
We know that she can only work a maximum of 15 hours per work total, and that at she must work at least 5 hours in the restaurant.
Therefore:
r + y ≤ 15
r ≥ 5
We also know that she wants to earn at least 120 dollars, earning $8/hr in the restaurant and $12/hr in the yard:
8r + 12y ≥ 120

What is the maximum of hours Lia can work in the restaurant and still make at leas 120 hours?
Lia's parents won't let her work more than 15 hours, so we know that the answer won't be higher than 15.
If she worked all 15 hours in the restaurant, she would make 8*15 = 120.
The maximum number of hours she can work in the restaurant is therefore 15 hours

What is the maximum amount of money Lia can earn in a week?
Lia has to work a minimum of 5 hours in the restaurant. She makes more money doing yard work, so she should devote the rest of her available work hours to yard work.
That means that, given her 15 hour work limit, she will maximize her income by working 5 hours in the restaurant and 10 hours in the yard.
5*8 + 10*12 = 40 + 120 = 160
The most she can make is 160 dollars, working 5 hours in the restaurant and 10 hours in the yard

7 0

3 years ago

Estimate 3 2/5 to the nearest integer

pickupchik [31]

4 is the nearest integer

as a decimal this number would be 3.5, which would round up to 4.

8 0

3 years ago

What is thirty times twenty

wariber [46]

Answer:

600

Step-by-step explanation:

How to do it in your head (secret):

3*2 = 6

add 2 zeros after the 6 since there are 2 zeros in total in this equation 20 and 30 so:

30*20 = 600

6 0

3 years ago

Read 2 more answers

There are 2,000 eligible voters in a precinct. A total of 500 voters are randomly selected and asked whether they plan to vote f

Ann [662]

Answer:

$0.7 - 2.58 \sqrt{\frac{0.7(1-0.7)}{500}}=0.647$

$0.7 + 2.58 \sqrt{\frac{0.7(1-0.7)}{500}}=0.753$

And the 99% confidence interval would be given (0.647;0.753).

So the correct answer would be:

a. 0.647 and 0.753

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Solution to the problem

The estimated population proportion for this case is:

$\hat p = \frac{350}{500}=0.7$

The confidence interval would be given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 99% confidence interval the value of $\alpha=1-0.99=0.01$ and $\alpha/2=0.005$ , with that value we can find the quantile required for the interval in the normal standard distribution.