Question
Four red balls, four green balls and four blue balls are put in a box. Three balls are pulled out of the box at random one after another without replacement. The probability that all the three balls are red is
Options :
1/72
1/55
1/36
1/27
Answer :
1/55
Solution :
Red balls = 4, Green balls = 4, Blue balls = 4
Total balls = 12
The probability that all three balls are red:
The way of selecting all the three red balls out of four red balls = 4C3
The ways of selecting 3 balls out of 12 balls = 12C3
P = 4C3 / 12C3
= 4/2x11x10 = 1/55
Copyright © 2025 Test Academy All Rights Reserved