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Question
A box B1 contains 1 white ball and 3 red balls. Another box B2 contains 2 white balls and 3 red balls. If one ball is drawn at random from each of the boxes B1 and B2, then find the probability that the two balls drawn are of the same colour.
Solution
| Box B1 | 1 White Balls 3 Red Balls |
| Box B2 | 2 White Balls 3 Red Balls |
∴ P(Required) = P(Both are white) + P(Both are red)
= `1/4 xx 2/5 + 3/4 xx 3/5`
= `20/20 + 9/20`
= `11/20`
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