Question

A train overtakes 2 persons walking at 3 km/hr and 5 km/hr respectively in the same direction and completely passes them in 8 seconds and 10 seconds respectively. find the speed of the train. 1) 15 km/hr 2) 13 km/hr 3) 10 km/hr 4) 10 km/hr 5) none of these

Answer 1

Assume the length of the train as D
x be the speed of the train

then.,
D/8=x-3
and
D/10= x-5

solving this 
8x-24 =10x-50
2x=26
x=13
ie.,speed of the train is 13km/hr