Question
Question: The no. of ways in which n<sup>2</sup> identical balls can be put in n numbered boxes (1, 2, 3, ……, ...
The no. of ways in which n2 identical balls can be put in n numbered boxes (1, 2, 3, ……, n) such that ith box contains at least i number of balls is-
A
n2Cn−1
B
n2−1Cn−1
C
n2+n−2Cn−1
D
None
Answer
n2+n−2Cn−1
Explanation
Solution
If we put minimum no. of balls required in each box, balls left are 2n(n−1)which can be put in n boxes in n2+n−2Cn−1ways without any restriction.