## Afrodiddle one year ago A store had 235 MP3 players in the month of January. Every month, 30% of the MP3 players were sold and 50 new MP3 players were stocked in the store. Which recursive function best represents the number of MP3 players in the store f(n) after n months? A. f(n) = 0.7 × f(n - 1) + 50, f(0) = 235, n > 0 B.f(n) = 237 - 0.7 × f(n - 1) + 50, f(0) = 235, n > 0 C.f(n) = 0.3 × f(n - 1) + 50, f(0) = 235, n > 0 D.f(n) = 237 + 0.7 × f(n - 1) + 50, f(0) = 235, n > 0

1. Afrodiddle

I believe it is A) but I am not entirely sure, can someone walk me through the steps?

2. anonymous

i agree, it is A. the first term $0.7\times f(n-1)$ represents 70% of the total MP3 players of the previous month, that is the remaining quantity since 30% were sold. the other term +50, represents the newly added MP3 players to the stock and if January is indexed by n=0, f(0) should be 235, as is in answer A so, answer A matches all the requirements!