Places A and B are 100km apart on a highway. One car starts at A and another from B at the same time. If the cars travel in the same direction at different speeds, they meet in 5 hours. If they travel towards each other, they meet in 1 hour. What is the difference between the speeds of two cars?

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

answer is B.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

Let the speed of the car at A be x kmph
and the speed of the car at B be y kmph
When car travels in same direction, Relative speed is x - y
Distance = 100 km
t = 5 hours
Therefore, Distance = S x T
100 = (x - y)5
x - y = 20……………….. (i)
When car travels in opposite direction, Relative speed is x + y
Distance = 100 km
t = 1 hour
Therefore, Distance = S x T
100 = (x + y)1
x + y = 100………..….. (ii)
Solving (i) and (ii)
x - y = 20