THERE ARE 4 SIXTEEN-YEAR-OLD GIRLS, 5 FIFTEEN-YEAR-OLD GIRLS AND 7...

11. - ĐỀ THI OLYMPIC TOÁN TMO VÒNG CÁ NHÂN 11. - ĐỀ THI OLYMPIC TOÁN TMO VÒNG CÁ NHÂN
Toán ĐỀ THI OLYMPIC TOÁN TMO VÒNG CÁ NHÂN

11.

There are 4 sixteen-year-old girls, 5 fifteen-year-old girls and 7 fourteen-year-old

girls. In how many ways can they be formed into 8 pairs so that the 2 girls in

each pair are of different ages?

Answer :

ways

2013 Asia Inter-Cities Teenagers Mathematics Olympiad

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