nguyendinhtuong
There are 3 boxes A, B and C. In box A, there are 3 green marbles and 5 yellow marbles. In box B, there are 2 red marbles and 3 green marbles. In box C, there are 4 white marbles and 5 green marbles. Choose randomly a box then pick randomly a marble from that box. What is the probability that picked marble is green?
A. 1/8
B. 55/96
C. 2/15
D. 551/1080
E. 551/360
The probability of picking a green marble from the different boxes is different.
Probability of picking box A = 1/3
Probability of picking a green marble from box A = 3/8
Probability of picking box B = 1/3
Probability of picking a green marble from box B = 3/5
Probability of picking box C = 1/3
Probability of picking a green marble from box C = 5/9
Probability of picking a green marble from box A, B or C = (1/3)*(3/8) + (1/3)*(3/5) + (1/3)*(5/9) = 1/8 + 1/5 + 5/27 = 551/1080