Question

^nCr = ________________

(a) n!

(b) \(\frac{n!}{r!}\)

(c) \(\frac{n!}{(n-r)!}\)

(d) \(\frac{n!}{(n-r)! r!}\)

This question was addressed to me during an online exam.

This intriguing question comes from Combinations in chapter Permutations and Combinations of Mathematics – Class 11

Answer 1

Correct answer is (d) \(\frac{n!}{(n-r)! r!}\)

The best I can explain: Permutation is known as selection. ^nCr means arranging r objects out of n.

^nCr = \(\frac{n!}{(n-r)! r!}\).