Question

There are two decks of cards.  Each deck has a red, a yellow, a blue, and a green card in it.  If a card is drawn, from the first deck, and then a second card drawn from the second deck, what is the probability that a red card or green card are drawn (not necessarily in that order)?

Answer 1

The total probability of success is 1/16 + 1/16 = 2/16 = 1/8

Explanation:

Answer 2

Probability of choosing Red first is 1/4
Probability of choosing Green second is 1/4 (this coming from the second deck)
The probability of choosing in this order is 1/4 * 1/4 = 1/16

Probability of choosing Green first is 1/4
Probability of choosing Red second is 1/4
The probability of choosing in this order is 1/4*1/4 = 1/16

The total probability of success is 1/16 + 1/16 = 2/16 = 1/8