31/05/2016
Probability
Box 1 contains 10 balls; 7 are marked "win" and 3 are marked "lose". Box 2 contains 10 balls; 3 are marked "win" and 7 are marked "lose". You roll a die. If the die shows 1 or 2, you select Box 1 and draw a ball. If you roll 3, 4, 5 or 6, you select Box 2 and draw a ball. Find the probability that Box 2 is selected if you have selected a "win."
a. 6/11
b. 6/15
c. 3/17
d. 4/23