To redeem a souvenir from a chain store, one must collect a set of five different types of coupons, namely A, B, C, D, E Suppose that a customer has collected 12 coupons independently, with each equally likely to be one of these five types.
(a) Find the probability that the customer has no coupon of type A.
(b) Find the probability that the customer has no coupon of type A and type B.
(c) Find the probability that the customer can redeem a souvenir.