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2 years ago

Conjecture: The difference between two negative numbers is always negative. Write a counterexample. *

Mathematics

1 answer:

Katen [24]2 years ago

4 0

If you add two negative numbers you get a sum that is less than both of the numbers. so -1+-2=-3

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Please answer! Will give brainliest. Have a good day:)

taurus [48]

Answer:

Step-by-step explanation:

Green: y = 1.75x + 4

The slope is 1.75 which is the rate per mile.

Green charges $1.75 per mile.

White:

For 3 miles: $10.50

For 5 miles: $13.50

Difference: $13.50 - $10. 50 = $3.00

The $3.00 difference is for 2 miles.

Rate per mile: $3.00/2 = $1.50

White charges $1.50 per mile

Answer: B.

6 0

2 years ago

A study of the amount of time it takes a mechanic to rebuild the transmission for a 1992 Chevrolet Cavalier shows that the mean

Dovator [93]

Answer:

B) 0.0069

Step-by-step explanation:

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

Normal probability distribution

Problems of normally distributed samples are solved using 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.

In this question, we have that:

$\mu = 8.4, \sigma = 1.8, n = 40, s = \frac{1.8}{\sqrt{40}} = 0.2846$

Find the probability that their mean rebuild time exceeds 9.1 hours.

This is 1 subtracted by the pvalue of Z when X = 9.1. So

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

By the Central Limit Theorem

$Z = \frac{9.1 - 8.4}{0.2846}$

$Z = 2.46$

$Z = 2.46$ has a pvalue of 0.9931

1 - 0.9931 = 0.0069

So the answer is B.

6 0

3 years ago

A cone has a volume 12 pie cubic inches it’s height 4 inches what is the radius?

insens350 [35]

Answer:

Step-by-step explanation:

The formula of a volume of a cone:

$V=\dfrac{1}{3}\pi r^2H$

r - radius

H - height

We have V = 12π in³ and H = 4 in. Substitute:

$12\pi=\dfrac{1}{3}\pi(r^2)(4)\qquad\text{multiply both sides by 3}\\\\36\pi=4\pi r^2\qquad\text{divide both sides by}\ 4\pi\\\\9=r^2\to r=\sqrt9\to r=3$