During a particular baseball game, the probability of a team's pitcher throwing a strike on each throw is 2/5. What is the least number of times that the pitcher should pitch the ball that will increase the probability of getting a strike at least once to more than 50%. Pick:	A) 3	B) 2	C) 1	D) 4	E) 5

Rationale: rule of subtraction : p ( a ) = 1 - p ( a ' ) rule of multiplication : p ( a ∩ b ) = p ( a ) p ( b ) the probability that the pitcher throws a strike at least once in 2 guesses is 1 - ( 3 / 5 ) ^ 2 = 1 - 9 / 25 = 16 / 25 > 50 % . answer : b
Answer: B