A probability problem by Sandeep Mishra

Probability Level 2

A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

3/22 2/91 1/22 2/77

Sandeep Mishra by Sandeep Mishra , 32, India

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2 solutions

Harish Chauhan
Apr 2, 2014

Since we have 5 red ball out of 15, so probability of getting all three ball red is

5C3/15C3=10/(5.7.13)=2/91 where C denotes combination and . indicates multiplication

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Probability = number of ways you can pick 3 red balls / number of ways you can pick any 3 balls

= 5 Choose 3 / 10 Choose 3 = 10 / 455 = 2 / 91

0 Helpful 0 Interesting 0 Brilliant 0 Confused

There might be a typo in your solution, it is 5 Choose 3/15 Choose 3 = 10/455 = 2/91 (The idea of the solution is correct, i don't mean any offense, just trying to point that mistake out to avoid confusion)

Sankalp Patro - 7 years, 2 months ago

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