RRB NTPC Mains or Stage 2 Model Paper 6 with solutions

Question : 37 of 119

Marks: +1, -0

Points A and B are 70 km apart on a highway. One car starts form A and the another one from B at the same time. If they travel in the same direction, they meet in 7 hours. But if they travel towards each other, they meet in one hour. The speeds of the two cars are, respectively.

45 and 25 km/h
70 and 10 km/h
40 and 30 km/h
60 and 40 km/h

Validate

Solution:

(c) Let the speed of the cars be x km/h and ykm/h, respectively.
Their relative speeds when they are moving in same direction = (x – y) km/h.
Their relative speeds when they are in opposite directions = (x + y) km/h.
Now, 7

0 /{x+y}=1or x + y = 70

..... (i)
and

70/{(x -y)}=7or x – y = 10

..... (ii)Solving (i) and (ii), we have x = 40 km/h and y = 30 km/h.

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