A taxi leaves the station X for station Y every 10 minutes. simultaneously, a taxi also leaves the station Y for station X every 10 minutes. The taxies move at the same constant speed and go from X to Y or vice versa in 2 hours. How many taxies coming from the other side will meet each taxi on route from Y to X.

From station X after every 10 minutes one taxi leaves for station Y. The time taken is 2 hours. From station Y, &taxi also leaves for station X, The situation is shown in figure.

Consider a taxi leaves station Y at 2 . 00PM for station X. It will meet all the 11 taxies marked in the figure which have started two hours before from station X as well as 12 other taxies which would leave the station X within two hours. There will be one more taxi leaving station X but it will not be counted among the taxies crossed by the taxi under consideration. Hence it will cross 11+12=23 twenty three taxies.