Going over previous exams for the final today and couldn't see why he marked this one wrong. It really bothers me when teachers simply mark something wrong without telling why. The problem states:
Three committees of respectively 4, 3, and 2 people are to be formed. They are to be formed from a group of 12 people. How many ways can this be done if:
a) No person can serve in more than one committee?
My solution : C(12,4) + C(8,3) + C(5,2) = 561
b) A person can serve in any number of committees?
My solution : C(12,4)+ C(12,3) + C(12,2) = 781
Three committees of respectively 4, 3, and 2 people are to be formed. They are to be formed from a group of 12 people. How many ways can this be done if:
a) No person can serve in more than one committee?
My solution : C(12,4) + C(8,3) + C(5,2) = 561
b) A person can serve in any number of committees?
My solution : C(12,4)+ C(12,3) + C(12,2) = 781
Facebook
Twitter