Question

A bag contains 42 balls. 18 balls are green, 11 are white and 13 are red. What is the minimum number of balls that must be picked up from the bag blindfolded (without replacing any of it) to be assured of picking at least one ball of each colour?

• A. 25
• B. 30
• C. 32
• D. 42

Answer 1

The correct option is C 32

First we need to select/remove all the balls of 2 colors which are more in number.
There is a chance that we select all the balls of 2 colours before selecting a ball of the third colour.
So, if I select 18 green balls and 13 red balls, the 32nd ball will surely be of white colour.