

InterviewSolution
Saved Bookmarks
1. |
Find the number of non-negative integral solutions of `x+y+z+wlt=20.` |
Answer» We have inequality, `x+y+z+w le 20` This is equivalent to equation x+y+z+w+t=20, where `t ge 0` Clearly number of non-negative integral solutions to (1) and (2) are same. So, number of solutions `= .^(20+5-1)C_(5-1)= .^(24)C_(4)` |
|