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counting and probability intermediate

Problem

The planning committee at school has 10 members. Exactly four of these members are teachers. A four-person subcommittee with at least one member who is a teacher must be formed from the members of the planning committee. How many distinct subcommittees are possible?
Solution
Because there are 4 teachers on the committee, there are 6 non-teachers. Now, in total, we can form subcomittees. The number of subcomittees with 0 teachers is the number of subcommittees formed by the 6 nonteachers, totaling . So, the number of subcomittees with at least 1 teacher is .
Final answer
195