Question

The number of ways in which three non-negative integers  can be chosen such that  is

Answer 1

go through this

http://math.stackexchange.com/questions/618491/distribute-n-identical-objects-into-r-distinct-groups

$\binom{n+r-1}{r-1}$ where n=10 r=3

$\binom{12}{2}$ = 66

Comments

sorry it's $\binom{12}{2}$ =66