To get a complete collection of stamps, Ann needs to have 5 specific (and different) kinds of stamps, denoted by k1, ... k5 . She starts out with no stamps. She then receives 5 stamps randomly from a lottery. Each of these 5 stamps has probability 1/5 of being of any particular kind ki , and the kinds of the different stamps she receives are independent.

Note: Enter numerical answers; do not enter '!' or combinations.

1 What is the probability that Ann has a complete collection after receiving the 5 stamps from the lottery?

2 Given that Ann does not have a complete collection after receiving the 5 stamps from the lottery, what is the probability that she is missing exactly one stamp?

2 answers

Anyone has any answer?

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