Question

SSC Test Questions

It takes eight hours for a 600 km journey, if 120 km is done by train and the rest by car. It takes 20 minutes more, if 200 km is done by train and the rest by car. The ratio of the speed of the train to that of the cars is ?

Answer 1

It travel 600km 120km by train and 600-120=480km by car in 8 hr............1 it travel 600km 200km by train and 400km by car in 8hr+(20/60)hr=25/3hr.......................2 v=d/t using eq 1. we know that (vt=velocity of train and vc=velocity of car) (120km/vt)+(480/vc)=8 lets suppose x=1/vt and y=1/vc 120x+480y=8 by dividing by 2, then 2, and then 2 we get 15x+60y=1......................3 using eq 2 we know that (200/vt)+(400/vc)=25/3 200x+400y=25/3 600+1200y=25 by dividing it by 5.then 5 , 24x+48y=1......................4 using 3 and 4.......... 15x+60y=24x+48y 12y=9x x/y=4/3 1/vt/1/vc=4/3 vt:vc=3:4 ratio of velocity = 3:4