9x mean 9 multipled with an unkown number and 9x is subtracted from another unknown number 'y' . you can substitute with any letters you want ,but you have to use two different letters.
Answer:
ans=13.59%
Step-by-step explanation:
The 68-95-99.7 rule states that, when X is an observation from a random bell-shaped (normally distributed) value with mean
and standard deviation
, we have these following probabilities



In our problem, we have that:
The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 53 months and a standard deviation of 11 months
So 
So:



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What is the approximate percentage of cars that remain in service between 64 and 75 months?
Between 64 and 75 minutes is between one and two standard deviations above the mean.
We have
subtracted by
is the percentage of cars that remain in service between one and two standard deviation, both above and below the mean.
To find just the percentage above the mean, we divide this value by 2
So:

The approximate percentage of cars that remain in service between 64 and 75 months is 13.59%.
First make the fraction over 100
21/50(2/2) = 42/100
42/100 = 0.42
0.42 is your answer
hope this helps
F−1(x)=4x+48 is your answer
Divide the total cost by the amount of months
28.5 divided by 6=4.75