4.17 Consider the following contingency table:

	B	B
A	10	30
A	25	35

What is the probability of

a. A I B?

b. A' I B?

c. A I B?

d. Are events A and B independent?

4.18 If P(A and B) = 0.4 and P(B) = 0.8, find P(A I B).

4.19 If P(A) = 0.7, P(B) = 0.6, and A and B are independent, find P(A and B).

4.20 If P(A) = 0.3, P(B) = 0.4, and P(A and B) = 0.2, are A and B independent?