Cities P and Q are 250 km apart. Two trains start from P and Q simultaneously. If they proceed in the same direction, they will encounter each other in 25 hours. If they travel towards each other, they meet in 5 hours. What is the speed of the slower train?
Show answer & explanation
Correct answer: A
Explanation
Distance between two cities = 250 km
Relative speed = 250 ÷ 5 = 50 km/h
Faster speed + Slower speed = 50
In the same direction -
Relative speed = 250 ÷ 25 = 10 km/h
Faster speed − Slower speed = 10
2 × Faster speed = 60
Faster speed = 30 km/h
Slower speed = 50 − 30 = 20 km/h