Buses come out of a bus terminus in intervals of 10 minutes at 20 km/h. A man coming from opposite direction towards the terminus meets the buses at intervals of 8 minutes. What is his speed?

Correct option is B

Let the speed of the man be x km/hr.
As we know,
Distance covered by the bus in 10 min = Distance covered by (bus and man) In 8 min.
Speed of bus and man (opposite direction) = (20 + x) km/hr
According to the question
20 × (10/60) = (20 + x) × (8/60)
⇒200 = (20 + x) 8
⇒ 160 + 8x = 200
⇒ 8x = 200 - 160
⇒ x = 40/8
⇒ x = 5 km/hr