Class 11

Math

JEE Main Questions

Permutations and Combinations

Let $f(n,k)$ denote the number of ways in which $k$ identical balls can be colored with $n$ colors so that there is at least one ball of each color. Then $f(2n,n)$ must be equal to a. $_{2}nC_{n}$ b. $_{2}n−1C_{n+1}$ c. $_{2}n−1C_{n}$ d. none of these