Question
A box contains only three colors of balls- red, green
and blue. What is the minimum number of balls that should be picked from the box to ensure that at least 6 red balls or at least 7 green balls or at least 9 blue balls are picked?Solution
If we pick at least 5 red balls, 6 green balls and 8 blue balls from the box, the total number of balls picked from the box will be 19. If one more ball is picked from the box, irrespective of what it is, it can be said that at least 6 red balls or at least 7 green balls or at least 9 blue balls have been picked from the basket. Hence, required number of balls = 19 + 1 = 20
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