Can someone explain how to solve this problem please. "In how many ways can a team of 4 be chosen from 13 people if 2 of the people refuse to work on the same team?"

Thanks in advance

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- May 20th 2013, 05:14 AMSahilShetHelp with "nCr" problems
Can someone explain how to solve this problem please. "In how many ways can a team of 4 be chosen from 13 people if 2 of the people refuse to work on the same team?"

Thanks in advance - May 20th 2013, 06:05 AMShakarriRe: Help with "nCr" problems
If person A and person B will not work together there are 3 scenarios

Case 1: Neither A nor B is chosen

Case 2: A is chosen and B isn't

Case 3: B is chosen and A isn't

Find out how many ways a team can be formed in each case.

Alternatively,

The 4th and last case is that both are picked which isn't allowed. The number number of ways A and B are chosen together plus the sum of the ways in which they aren't chosen together is the total number of ways you can make a team of 4 without restrictions.