Engineering Board Exam Reviewer · Combinations · hard
In how many ways can 10 people be divided into two groups of 5 people each (the groups are not labeled)?
- 252
- 63
- 126
- 1,260
Answer
C. 126
Solution
Choosing one group of 5 gives 10C5=252 ways, but each division is counted twice (the other group is the complement). So 252/2=126.
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