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## 'How Many Balls?' printed from http://nrich.maths.org/

A bag contains an assortment of red and blue balls. Two balls
are drawn at random.

You are told that the probability of drawing two red balls is 5
times the probability of drawing two blue balls. Furthermore, the
probability of drawing one ball of each colour is 6 times the
probability of drawing two blue balls.

How many blue and how many red balls are in the bag?