Question

4. Corrupt professor Z has a class of 50 students. He needs to give exactly 10 A's. However five students already have a special deal (they are professor Z's nephews and nieces) and will get A's for sure. How many ways can the 10 A's be distributed?

Answer 1

Explanation:

Given that the professor Z has a class of 50 students is corrupt. However five students already have a special deal (they are professor Z's nephews and nieces) and will get A's for sure.

Thus out of 10 students 5A's are reserved

Remaining 5 can be distributed in

I 5 to any one of the 45, II to any one of the 44....

i.e. 45P5 ways

no of ways = 45P5 == 146611080