help with 2 questions

11. If P(A) = 0.3 and P(AUB) = .88 and P(A intersect B) = .12, then P(B)= ?:                    .88 = .3 + P(B) – (.12)  solve for P(B)

4. Of five letters (A,B,C,D, and E), two letters are to be selected at random. How many possible selections are there?:

a. 20

b. 7

c. 5!

d. 10

e. 22