A bag contains 30 tokens numbered serially from 0 to 29. The number of ways of selecting 3 tokens from the bag, such that sum of numbers on them is 30, is
one of the coin | other two coins | No. of ways |
0 | (1,29).....(14,16) | 14 |
1 | (2,27).....(14,15) | 13 |
2 | (3,25).....(13,15) | 11 |
3 | (4,23).....(13,14) | 10 |
4 | (5,21).....(12,14) | 8 |
5 | (6,19)....(12,13) | 7 |
6 | (7,17)...(11,13) | 5 |
7 | (8,15)..(11,12) | 4 |
8 | (9,13)(10,12) | 2 |
9 | (10,11) | 1 |