According to the National Center for Health Statistics, life expectancy for a 70-year-old American male is 14.5 years. Assuming that, from age 70, the survival of American males follows an exponential distribution, determine the following probabilities.

(a) The probability that a randomly selected 70-year-old American male will live beyond 90 years of age
(b) The probability that a randomly selected 70-year-old American male will live between 10 and 20 more years