Question

John walks to a place with a speed of 4 km/h in 3 hrs 45 min and returns back on a bicycle. If the speed of the bicycle is thrice that of his speed, then how much time will he take to return?  
1. 1 hr 20 min
2. 1 hr 25 min
3. 1 hr 15 min
4. 1 hr 10 min

Answer 1

Correct Answer - Option 3 : 1 hr 15 min

GIVEN:
Walking speed = 4 km/h

Time = 3 hrs 45 min

Bicycle's speed = 3 × Walking speed

FORMULA USED:
Speed = Distance/Time

CALCULATION:

Time = 3 hrs 45 min = 15/4 hrs

Distance = 4 × 15/4 = 15 km

Bicycle's speed = 3 × 4 = 12 km/h

Return time = 15/12 = 1 + 1/4 hrs

⇒ 1 hr 15 min

∴ He will take 1 hr 15 min to return.