Practicing Success
40 persons are sitting in a row. How many persons are sitting between $31^{st}$ person from left and $25^{th}$ person from right ? |
18 15 20 21 |
15 |
Total = 31st person from left + 25th person from right - 1 40 = 31 + 25 - 1 40 - 31 - 25 + 1 15 |