06/19/2020 (2011: Countdown Round, Problem 11)

Q: Raul must randomly choose two iPods®. There are 4 white, 3 red, 1 purple and 2 blue iPods on the store's shelf . Assuming he chooses the purple iPod first, what is the probability he will randomly select a white iPod second? Express your answer as a common fraction.

A: 4/9

There are 4 + 3 + 1 + 2 = 10 iPods, before Raul chooses one. That means there are 10 - 1 = 9 iPod after he chooses one.

There are 4 white iPods if Raul chooses a purple one first, so the probability is 4/9.