Official Explanation
To determine the number of different combinations of 3 of the remaining candidates that the manager has to choose from, you first have to know the number of remaining candidates. Since you know that the manager has already chosen 3 of the 11 candidates to be on the team, it is easy to see that there are 8 remaining candidates. Now you need to count how many different combinations of 3 objects can be chosen from a group of 8 objects.
If you remember the combinations formula, you know that the number of combinations is \(\frac{8!}{3!(8-3)!}\). You can then calculate the number of different combinations of 3 of the remaining candidates as follows.
\(\frac{8!}{3!(8-3)!} =\frac{8*5*6*5!}{(3!)(5!)} = \frac{8*7*6}{6} = 56\)
The correct answer is Choice C.