It being given that Pinky is 21st from the right end and Rinky is 10th to the left of Pinky, Rinky’s position from the right end is 21 + 10 = 31th It being given that Minky is 4th to the right of Rinky, so Minky’s position from the right end is 31 – 4 = 27th Minky’s position from the left end is 17th. From these two positions of Minky from the left end and the right end in the row, the number of total girls = 27 + 17 – 1 = 43