Day 5
Ash decides to buy 100 of each Pikachu, because he is rich. 33 are male, and 37 are female. Ash wants his own Pikachu family. If a Pikachu family includes 25 males, and 25 females, how many distinct Pikachu families are there? Divide your answer by 10^13, and round to the nearest whole number.
Details and Assumptions
All Pikachus are different. The order of Pikachus in the family does not matter.
The answer is 2572.
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1 solution
Instead of choosing the members of the family, choose the members outside the family. 33 choose 8, for males, and 37 choose 12. ((33 32 31 … 26)÷8!) ((37 36 35 …*26)÷12!) is about 2572 * 10^13. If there are problems in my calculation, or the problem itself is confusing, please reply.