Answer:
181 MP3 players
Explanation:
Given data:
Replacement of MP3 that fail within 3 years
expected lifetime of MP3 = 5 years
number of MP3 players purchased = 1000
number of MP3 players replaced in the first year = ?
To determine the number of MP3 replaced in the first year we will employ this formula:

a = ∞
since the given problem is an exponential distribution
1/u = 5 hence u = 0.2
next we will determine the number of MP3's to fail in its first year of purchase
qo = failure
po = success
number of purchase = 1000
attached below is the remaining part of the solution