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Exercise 443Combinatorics › Counting principlesHigh schoolAdded 3 Nov 2026

Choosing a mixed committee

#combinations#committee#product rule

Statement

From 77 men and 55 women, how many committees of 44 containing at least 22 women can be formed?

Hint

Sum over the number of women (22, 33, 44).

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Solution

Cases.
- 22 women, 22 men: (52)(72)=10⋅21=210\binom{5}{2}\binom{7}{2}=10\cdot21=210.
- 33 women, 11 man: (53)(71)=10⋅7=70\binom{5}{3}\binom{7}{1}=10\cdot7=70.
- 44 women: (54)=5\binom{5}{4}=5.

Total. 210+70+5=285210+70+5=285.

Conclusion. There are 285285 such committees.