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JEE MATHEMATICS MCQ: COMBINATIONS

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There are four balls of different colours and four boxes of colours same as those of the balls. The number of ways in which the balls, one in each box, could be placed such that a ball does not go to box of its own colour, is

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Correct option: C

9

Option C (9) is correct because it represents the number of derangements of 4 items, which can be calculated using the formula or by listing out the possibilities.

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n