Answer
(a) Evaluating this integral tells us the probability that the tire will last between 30,000 miles and 40,000 miles.
(b) Evaluating this integral tells us the probability that the tire will last 25,000 miles or more.
Work Step by Step
(a) $\int_{30,000}^{40,000}f(x)~dx$
Evaluating this integral tells us the probability that the tire will last between 30,000 miles and 40,000 miles.
(b) $\int_{25,000}^{\infty}f(x)~dx$
Evaluating this integral tells us the probability that the tire will last 25,000 miles or more.
