Source: Official Guide Revised GRE 1st Ed. Part 6; Set 3; #7

3

A manager is forming a 6-person team

A manager is forming a 6-person team to work on a certain project. From the 11 candidates available for the team, the manager has already chosen 3 to be on the team. In selecting the other 3 team members, how many different combinations of 3 of the remaining candidates does the manager have to choose from? 6, 24, 56, 120, 462

2 Explanations

1

Sarah Beaulieu

Why does the 3 factorial cancel out the 6 factorial on top? I followed you all the way up until the end.

Sep 22, 2017 • Comment

Sam Kinsman, Magoosh Tutor

Happy to help! We have (8*7*6) / (3!). Notice that on top, we don't have 6!, it is just 8*7*6. Now, 3! = 3*2*1 = 6. So we have:

(8*7*6) / (3!) = (8*7*6) / 6

Here we can cancel the two sixes, and we are left with 8*7 = 56

Oct 19, 2017 • Reply

2

Gravatar Chris Lele, Magoosh Tutor

Oct 7, 2012 • Comment

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