# Coupon Collector Problem

Coupon Collector Problem

If a package has one of 50 random baseball cards, how many packages do you need to buy to get a complete set? The expected answer is packages, where is the harmonic number . Switching from baseball cards to coupons gives the coupon collector problem: if there are different kinds of coupons and many of them are distributed randomly, the expected number of purchases necessary for a complete set is .

50≈225

H

50

H

50

1/1+1/2+1/3+…+1/50

n

n

H

n