Answer: the probability that a randomly selected tire will have a life of exactly 47,500 miles is 0.067
Explanation:
Since the life expectancy of a particular brand of tire is normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = life expectancy of the brand of tire in miles.
µ = mean
σ = standard deviation
From the information given,
µ = 40000 miles
σ = 5000 miles
The probability that a randomly selected tire will have a life of exactly 47,500 miles
P(x = 47500)
For x = 47500,
z = (40000 - 47500)/5000 = - 1.5
Looking at the normal distribution table, the probability corresponding to the z score is 0.067