Monday, February 25, 2013

Probability using the Exponential distribution?

Alice has purchased a new iPad, which is defective; it catches fi re spontaneously. Let
X = the amount of time in years until the iPad catches fire, and suppose X  Exp(5).

Every 3 years Apple releases a new iPad model and Alice dutifully replaces her
old iPad with a new one. What is the probability that Alice will replace her iPad
before it catches re? (Answer: 0:550671)

I get e^(-3/5) which is close to the answer, but not quite right. What am I doing wrong? Thanks!
>>> Probability using the Exponential distribution?