Madhu is 18th from the left end Sandhu is 11th from right end of row of 40 children. How many children are there between Madhu and Sandhu in the row?

10 9 12 11

11

T = L +R - 1 40 = 18 + R - 1 R = 23 (Madhu's position from right) P1 - P2 - 1 23 - 11 - 1  = 11