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3 years ago

What is the multiplicative inverse of -7 9

1 answer:

5 0

Since multiplicative inverse is the same thing as reciprocal, the multiplicative inverse is just the denominator and the numerator flipped. So the multiplicative inverse of -7/9 is 9/-7. Hope this helps! If you ever need any more help in math you could always DM me.

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To go on the class trip, Chang needs at least $125. He has saved $45, and he makes $7 an hour at his job. What is the minimum nu

Karolina [17]

To start off, Chang has already saved $45. $125 - $45 = $80. Therefore, he owes $80. $80 ÷ 7 = 11.4285714286, so he needs to work 12 full hours to pay for his trip.

8 0

3 years ago

A programmer plans to develop a new software system. In planning for the operating system that he will use, he needs to estimat

Vedmedyk [2.9K]

Using the z-distribution, we have that:

a) A sample of 601 is needed.

b) A sample of 93 is needed.

c) A. Yes, using the additional survey information from part (b) dramatically reduces the sample size.

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $\alpha$ , we have the following confidence interval of proportions.

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

In which z is the z-score that has a p-value of $\frac{1+\alpha}{2}$ .

The margin of error is:

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

95% confidence level, hence $\alpha = 0.95$ , z is the value of Z that has a p-value of $\frac{1+0.95}{2} = 0.975$ , so $z = 1.96$ .

For this problem, we consider that we want it to be within 4%.

Item a:

The sample size is <u>n for which M = 0.04.</u>

There is no estimate, hence $\pi = 0.5$

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

$0.04 = 1.96\sqrt{\frac{0.5(0.5)}{n}}$

$0.04\sqrt{n} = 1.96\sqrt{0.5(0.5)}$

$\sqrt{n} = \frac{1.96\sqrt{0.5(0.5)}}{0.04}$

$(\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.5(0.5)}}{0.04}\right)^2$

$n = 600.25$

Rounding up:

A sample of 601 is needed.

Item b:

The estimate is $\pi = 0.96$ , hence:

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

$0.04 = 1.96\sqrt{\frac{0.96(0.04)}{n}}$

$0.04\sqrt{n} = 1.96\sqrt{0.96(0.04)}$

$\sqrt{n} = \frac{1.96\sqrt{0.96(0.04)}}{0.04}$

$(\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.96(0.04)}}{0.04}\right)^2$

$n = 92.2$

Rounding up:

A sample of 93 is needed.

Item c:

The closer the estimate is to $\pi = 0.5$ , the larger the sample size needed, hence, the correct option is A.

For more on the z-distribution, you can check brainly.com/question/25404151

8 0

2 years ago

In a survey of 364 children aged 19-36 months, it was found that 91 liked to eat potato chips. If a child is selected at random,

n200080 [17]

Answer: 0.75

Step-by-step explanation:

A survey of 364 children aged 19-36 months found that 91 liked to eat potato chips.

Total children surveyed= 364

Those that like to eat potato chips= 91

Those that don't like to eat potato chips= 364 - 91 = 273

Probability that the child chosen doesn't like to eat potato chips will be children that don't like to eat potato chips divided by total number of children surveyed.

= 273/364

= 0.75

4 0

3 years ago

A student says that the x-intercept of the graph of × + 2y =5 is the point (0,5). Is the student correct or incorrect? Explain y

ivanzaharov [21]

The student is incorrect, the actual x-intercept is (5, 0).

<h3>Is the student correct or incorrect?</h3>

Here we have the equation:

x + 2y = 5

The student says that the x-intercept is the point (0, 5).

So if you look at the point you already can see that the student is incorrect, this is because the x-intercept always must have a y-value of 0. (the graph only intercepts the x-axis when y = 0).

So the point (0, 5) can't be an x-intercept.

For the given function:

x +2y = 5

The x-intercept is given by:

x + 2*0 = 5

x = 5

So it is (5 , 0).

If you want to learn more about x-intercepts:

brainly.com/question/3951754

#SPJ1

5 0

2 years ago

I need help on question 2 please

Romashka-Z-Leto [24]

Answer is 148,847,750

3 0

3 years ago

Read 2 more answers