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Question

Mathematics Question on permutations and combinations

There are 4 men and 5 women in Group A, and 5 men and 4 women in Group B. If 4 persons are selected from each group, then the number of ways of selecting 4 men and 4 women is

Answer

We need to select 4 men (M) and 4 women (W) from the two groups. Consider the following cases:

From Group A\text{From Group A}From Group B\text{From Group B}Ways of Selection\text{Ways of Selection}
4M4W(44)(44)=1{{4}\choose{4}} \cdot {{4}\choose{4}} = 1
3M1W1M3W(43)(51)(53)(41)=400{{4}\choose{3}} \cdot {{5}\choose{1}} \cdot {{5}\choose{3}} \cdot {{4}\choose{1}} = 400
2M2W2M2W(42)(52)(52)(42)=3600{{4}\choose{2}} \cdot {{5}\choose{2}} \cdot {{5}\choose{2}} \cdot {{4}\choose{2}} = 3600
1M3W3M1W(41)(53)(51)(43)=1600{{4}\choose{1}} \cdot {{5}\choose{3}} \cdot {{5}\choose{1}} \cdot {{4}\choose{3}} = 1600
4W4M(54)(54)=25{{5}\choose{4}} \cdot {{5}\choose{4}} = 25
Total5626

Final Answer: 5626.