M-2

2. Let A denote the event that the next student to come to Think Tank will need help with MATH 330, and let B denote the event that the next student will need help with PHYS 101. Suppose that P(A) = 0.3 and P(B) = 0.5. (a) Why is it not the case that P(A) + P(B) = 1? (b) Interpret the event A and calculate its probability. (c) Interpret the event AU B and calculate its probability. (d) Interpret the event A'n B' and calculate its probability