Question

a class of 5n students, with 3n boys and 2n girls, wants to select n students to write a report. how many ways are there to select the n students, so that at least one girl is selected?

Answer 1

To solve this problem, we can use the principle of inclusion-exclusion.

First, let's find the total number of ways to select n students from a class of 5n:

Total ways = (5n choose n) = (5n)! / (n!*(5n-n)!) = (5n)! / (n!*(4n)!)