A 600 km travel takes eight hours if 120 km is covered by train and the remainder by vehicle. If you travel 200 kilometres by rail and the remainder by vehicle, it will take you 20 minutes longer. The ratio of the speed of the train to that of the cars is:
A. 2 : 3
B. 3 : 2
C. 3 : 4
D. 4 : 3
Answer:C
A 600 km travel takes eight hours if 120 km is covered by train and the remainder by vehicle. If you travel 200 kilometres by rail and the remainder by vehicle, it will take you 20 minutes longer. The ratio of the speed of the train to that of the cars is:
A. 2 : 3 B. 3 : 2 C. 3 : 4 D. 4 : 3
Explanation: Let's say the train's speed is x km/hr and the car's is y km/hr.Then, 120 /x+ 480 /y = 8 /x 1/y + 4/15 = 1.... (i)Also, 200/x + 400/y = 25/3 1/x + 2/y = 1/24 (ii).We obtain x = 60 and y = 80 when we solve I and (ii).60 : 80 = 3 : 4 is the speed ratio.