Question

A bag contains 3 red, 2 white and 4 green balls. What is the probability of drawing the second ball to be white if the first ball drawn is white? The balls are replaced in the bag.

(a) \(\frac {1}{9}\)

(b) \(\frac {2}{9}\)

(c) \(\frac {1}{8}\)

(d) \(\frac {2}{8}\)

The question was posed to me during an internship interview.

The doubt is from Multiplication Theorem on Probability topic in portion Probability of Mathematics – Class 12

Answer 1

The correct choice is (c) \(\frac {1}{8}\)

Easiest explanation: Total number of balls = 9

The probability of the first ball to be white = \(\frac {2}{9}\)

The probability of drawing white ball again for the second time without replacement = \(\frac {1}{8}\)