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3 years ago

The area of a rectangular folder is 63 square inches. The folder is 7 inches wide. How long is

Mathematics

2 answers:

ra1l [238]3 years ago

6 0

It’s 9inches ! Because area=width •length

Therefor you can divide 63 by 7 to get 9

Yakvenalex [24]3 years ago

6 0

Answer:

9 inches long

Step-by-step explanation: So, this is an area problem. We know that this is a rectangle. This means we use the equasion lw or length times width. We are missing the length so we can divide the area by the width. This is common in problems where you must find a missing number.

You might be interested in

"Five divded by the sum of a and b" written as a fraction would be

s2008m [1.1K]

Answer:

5/a+b

Step-by-step explanation:

5 0

3 years ago

The sum of four consecutive odd integers is 328. What are the integers? (show your work)

Minchanka [31]

Answer:

79, 81, 83, and 85

Step-by-step explanation:

x = 1st integer

x+2 = 2nd

x+4 = 3rd

x+6 = 4th

328 = sum

x+x+2+x+4+x+6 = 328

328/4 = 82

The 4 integers are the 2 odd integers on either side of 82 and closest to 82

That would be 79, 81, 83, and 85.

79 + 81 + 83 + 85 = 328

8 0

3 years ago

A Government company claims that an average light bulb lasts 270 days. A researcher randomly selects 18 bulbs for testing. The s

Fofino [41]

Answer:

31.92% probability that 18 randomly selected bulbs would have an average life of no more than 260 days

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

In this question, we have that:

$\mu = 270, \sigma = 90, n = 18, s = \frac{90}{\sqrt{18}} = 21.2$

What is the probability that 18 randomly selected bulbs would have an average life of no more than 260 days?

This is the pvalue of Z when $X = 260$ . So

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{260 - 270}{21.2}$

$Z = -0.47$

$Z = -0.47$ has a pvalue of 0.3192.

31.92% probability that 18 randomly selected bulbs would have an average life of no more than 260 days

5 0

3 years ago

Is the quotient of 3/5 ÷ 6/7 greater than or less than 3/5? Explain

Vikki [24]

The quotient of two fraction is the multiplication between the first and the inverse of the second:

$\dfrac{a}{b} \div \dfrac{c}{d} = \dfrac{a}{b} \cdot \dfrac{d}{c}$

So, in your case, you have

$\dfrac{3}{5} \div \dfrac{6}{7} = \dfrac{3}{5} \cdot \dfrac{7}{6} = \dfrac{7}{10}$

So, the question now is: which is larger, 7/10 or 3/5? To answer this question, transform the second fraction so that it will have denominator 10 as well:

$\dfrac{3}{5} = \dfrac{3\cdot 2}{5 \cdot 2} = \dfrac{6}{10}$