Question

In CAT entrance examination paper there are 3 sections, each containing 5 questions. A candidate has to solve 5 questions, choosing at least one from each section. The number of ways he can choose is:

Answer 1

He can choose...

1) 2 questions each from 1st & 2nd sets & 1 question from 3rd set...
2) 2 questions each from 1st & 3rd sets & 1 question from 2nd set...
3) 2 questions each from 2nd & 3rd sets & 1 question from 1st set...

Hope my answer is complete... Plz mark as Brainliest if I helped U...

Answer 2

It is the question of COMBINATION..........= nCr = n!/r!(n-r)!

Here in your case, n=5 & r=3 so,

5C3 = 5!/3!(5-3)!  = 5! /3! * 2!

You can write it as,  =5 * 4 * 3 * 2 * 1 / 3 * 2 * 1 * 2 * 1

 = 20/2  =  10.

So, the number of ways he can choose is 10.