A company repairs copiers and it is known that the time to repair a copier is normally distributed with a mean of 75 minutes and a standard deviation of 20 minutes. Approximately nineteen percent of the service calls take more than how many minutes?

Approximately nineteen percent of the service calls take more than 92.6 minutes.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

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

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.

In this problem, we have that:

Approximately nineteen percent of the service calls take more than how many minutes?

This is the value of X when Z has a pvalue of 1 - 0.19 = 0.81. So it is X when Z = 0.88.

Approximately nineteen percent of the service calls take more than 92.6 minutes.

b

step-by-step explanation:

the word superfluous means unnecessary

step-by-step explanation:

we are given

since, we have to isolate x on anyone side

so, we can move all x terms on one side

subtract both sides by 2x

add both sides by 9

divide both sides by 4

we get