Saved Bookmarks
| 1. |
Find the number of positive Integral solutions of x+y+z=20 if x ne y ne z : |
|
Answer» 144 Required solution `PHI` Total POSITIVE Integral solution `-` (any two are equal) `-` (`x=y=z` not possible) `rArr .^(19)C_(2)-overset("lit (3 cases)")((x=y ne z))(z = 20-2y)` `rArr .^(19)C_(2)-3xx(y=1, 2, .....,0)` `rArr .^(19)C_(2)-3xx9 rArr 171 - 27 = 144` |
|