Your truck tires are rated at? 45,000 miles. what is the probability that this? tire’s tread life will fall between? 44,500 and? 47,500 miles? assume the mean tire life is? 45,000 miles and the standard deviation is? 3,000 miles.

We are given:

45,00 miles is the actual tread life of the tire. 
The standard deviation is 3,000 miles
The mean of the tire life is 45,000 miles

The range of the tread life is:

45,000 - 3,000 = 42,000 miles
to 
45,000 + 3,000 = 48,000 miles

The probability that the tire tread life will fall between 44,500 and 47,500 miles can be determined by testing several tire samples. 

J= r + 9 because since jessica rode 9 more miles than roger, you add 9 miles to rogers mileage.