A mechanic sells a brand of automobile tire that has a life expectancy that is normally distributed, with a mean life of 27 comma 000 miles and a standard deviation of 2100 miles. He wants to give a guarantee for free replacement of tires that don't wear well. How should he word his guarantee if he is willing to replace approximately 10% of the tires?

Tires that wear out by approximately 24307.8 miles will be replaces free of charge.        

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 27,000 miles

Standard Deviation, σ = 2100  miles

We are given that the distribution of life expectancy is a bell shaped distribution that is a normal distribution.

Formula:

We have to find the value of x such that the probability is 0.10

Calculation the value from standard normal z table, we have,  

Tires that wear out by approximately 24307.8 miles will be replaces free of charge.

-1/2 +2

step-by-step explanation:

24+x=y

step-by-step explanation: