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'Weekly Problem 13 - 2014' printed from http://nrich.maths.org/

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A bag contains hundreds of glass marbles, each one coloured either red, orange, green or blue. There are more than 2 marbles of each colour.

Marbles are drawn randomly from the bag, one at a time, and not replaced.

How many marbles must be drawn from the bag in order to ensure that at least three marbles of the same colour are drawn?


This problem is taken from the UKMT Mathematical Challenges.

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