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3 years ago

How do I solve this properly?

Mathematics

1 answer:

o-na [289]3 years ago

6 0

Answer:

x $\geq$ 4

Step-by-step explanation:

4x^2 - 64 $\geq$ 0 ; move 64 over

4x^2 $\geq$ 64 ; divide by 4

x^2 $\geq$ 16 ; take square root of both sides

x $\geq$ 4

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The amount of time all students in a very large undergraduate statistics course take to complete an examination is distributed c

Anestetic [448]

Answer:

a) The mean is $\mu = 60$

b) The standard deviation is $\sigma = 9$

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be 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.

The probability a student selected at random takes at least 55.50 minutes to complete the examination equals 0.6915.

This means that when X = 55.5, Z has a pvalue of 1 - 0.6915 = 0.3085. This means that when $X = 55.5, Z = -0.5$

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

$-0.5 = \frac{55.5 - \mu}{\sigma}$

$-0.5\sigma = 55.5 - \mu$

$\mu = 55.5 + 0.5\sigma$

The probability a student selected at random takes no more than 71.52 minutes to complete the examination equals 0.8997.

This means that when X = 71.52, Z has a pvalue of 0.8997. This means that when $X = 71.52, Z = 1.28$

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

$1.28 = \frac{71.52 - \mu}{\sigma}$

$1.28\sigma = 71.52 - \mu$

$\mu = 71.52 - 1.28\sigma$

Since we also have that $\mu = 55.5 + 0.5\sigma$

$55.5 + 0.5\sigma = 71.52 - 1.28\sigma$

$1.78\sigma = 71.52 - 55.5$

$\sigma = \frac{(71.52 - 55.5)}{1.78}$

$\sigma = 9$

$\mu = 55.5 + 0.5\sigma = 55.5 + 0.5*9 = 55.5 + 4.5 = 60$

Question

The mean is $\mu = 60$

The standard deviation is $\sigma = 9$

6 0

3 years ago

Khloe's car used 8 gallons of gas to drive 272 miles. At what rate does her car use gas in gallons per mile? Express your answer

marin [14]

Answer: (You have to do a tiny bit of work, but im practically giving you the answer)

Step-by-step explanation: We’re trying to find out how many gallons of gas it takes to drive 1 mile.

1. So, 8 divided by 272= 0.02941176

2. Simplify 0.02941176 and you have your answer!

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3 years ago

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What is 33 photos into two grours so the ratio is 4 to 7

Keith_Richards [23]

$ratio:\\4:7\to4+7=11\\\\33:11=3\\\\therefore\\\\4:7\\\downarrow\\4\times3=12\\7\times3=21\\\\Answer\huge\boxed{12:21}$

7 0

3 years ago

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Which of the following is one solution to the expression (ax + b)(cx - d) = 0 ?

V125BC [204]

We know that
if (ax + b)(cx - d) = 0
then
(ax + b)= 0-----> ax=-b------> x=-b/a
and
(cx - d) = 0-----> cx=d------> x=d/c

therefore

the answer is the option
C. -\frac{b}{a}

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3 years ago

Zebediah is an American traveling with a tour group in Eastern Europe. During a stop in Rommania, he purchases a souvenir that i

denis23 [38]

So 1 USD is 2.89 RON
That means...
177 ÷ 2.89 = 61.24USD

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3 years ago