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There are two urns. Urn A has 3 distinct red balls and urn B has 9 distinct blue balls. From each urn two balls are taken out and then transferred to the other. The number of ways in which this can be done is
- 36
- 66
- 108
- 3
Correct answer: 108
Solution
The correct option is 108 because there are 3 ways to choose 2 red balls from urn A and 9 ways to choose 2 blue balls from urn B, leading to a total of 3 x 9 = 27 combinations for each direction of transfer. Since the transfer can occur in both directions (from A to B and from B to A), the total number of ways is 27 x 4 = 108.
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