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3 years ago

Please help! click to see the picture

Mathematics

1 answer:

Roman55 [17]3 years ago

4 0

Answer:
Inequality 7n - 22 >= 64
Solution 7n > = 64 + 22
7n >= 86
n => 12. 28 rounded down to 12
Grace must wash at last 12 cars

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The sum of three numbers is 75. The third number is 2 times the first. The second number is 9 less than the first. What are the

anygoal [31]

Let the three numbers be x, y and z. Then x+y+z=75.
z = 2x. y = x - 9.

Eliminate y and z by substitution: x + (x - 9) + (2x) = 75

Then 4x = 75 + 9, or 4x = 84. x = 21, y = 21 - 9 = 12, and z = 2(21) = 42.

Check: Do 21, 12 and 42 add up to 75?

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3 years ago

Suppose that the times required for a cable company to fix cable problems in its customers’ homes are uniformly distributed betw

vampirchik [111]

Answer:

a) 60% probability that a randomly selected cable repair visit will take at least 50 minutes

b) 60% probability that a randomly selected cable repair visit will take at most 55 minutes.

c) The expected length of the repair visit is 52.5 minutes.

d) The standard deviation is 7.22 minutes.

Step-by-step explanation:

An uniform probability is a case of probability in which each outcome is equally as likely.

For this situation, we have a lower limit of the distribution that we call a and an upper limit that we call b.

The probability that we find a value X lower than x is given by the following formula.

$P(X \leq x) = \frac{x - a}{b-a}$

For this problem, we have that:

Uniformly distributed between 40 and 65 minutes, so $a = 40, b = 65$

(a) What is the probability that a randomly selected cable repair visit will take at least 50 minutes?

Either it takes less than 50 minutes, or it takes at least 50 minutes. The sum of the probabilities of these events is decimal 1. So

$P(X < 50) + P(X \geq 50) = 1$

The intervals can be open or closed, so

$P(X < 50) = P(X \leq 50)$

We have that

$P(X \geq 50) = 1 - P(X < 50)$

$P(X < x) = \frac{50 - 40}{65 - 40} = 0.4$

$P(X \geq 50) = 1 - P(X < 50) = 1 - 0.4 = 0.6$

60% probability that a randomly selected cable repair visit will take at least 50 minutes

(b) What is the probability that a randomly selected cable repair visit will take at most 55 minutes?

This is $P(X \leq 55)$

$P(X \leq 55) = \frac{55 - 40}{65 - 40} = 0.6$

60% probability that a randomly selected cable repair visit will take at most 55 minutes.

(c) What is the expected length of the repair visit?

The mean of the uniform distribution is:

$M = \frac{a+b}{2}$

$M = \frac{40+65}{2} = 52.5$

The expected length of the repair visit is 52.5 minutes.

(d) What is the standard deviation?

The standard deviation of the uniform distribution is

$S = \sqrt{\frac{(b-a)^{2}}{12}}$

$S = \sqrt{\frac{(65-40)^{2}}{12}}$

$S = 7.22$

The standard deviation is 7.22 minutes.

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3 years ago

A store spends 30% of its budget on maintenance. its yearly budget is $150,000.how much is spent on maintenance?

joja [24]

It would be: 150,000*0.30 = 45000

so, your answer is $45,000

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3 years ago

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Use the properties of exponents to rewrite the expression <br> 3•b•b•b•b•b•c•c•c•c•c

frosja888 [35]

$3\cdot b\cdot b\cdot b\cdot b\cdot b\cdot c\cdot c\cdot c\cdot c\cdot c =3b^5c^5$

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3 years ago

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Sarah and Kelvin are calculating the area of a circle with a radius of 52 cm. Kelvin uses 3.14 for pi when calculating this area

TiliK225 [7]

Answer:

Correct

The solution is Sarah; The pi button on the calculator gives a more accurate representation for pi than 3.14. Using 3.14 as an approximation for pi yields a less accurate result.

Step-by-step explanation:

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3 years ago