RRB NTPC · Question 80
Two school vans start from a house at an interval of 8 minutes and travel with a speed of 25 km/hr. With how much speed (km/hr) should a woman coming from the opposite direction towards the house travel, to meet the vans at an interval of 4 minutes?
Show answer & explanation
Answer: (A) 25
Explanation
Vans 8 minutes apart at 25 km/h are 25 × 8/60 = 10/3 km apart. The woman meets them every 4 minutes, so (25 + v) × 4/60 = 10/3, which gives 25 + v = 50 and v = 25 km/h.