2017 · Q40
A boy went to his school at a speed of 12 km/hr and returned to his house at a speed of 8 km/hr. If he has taken 50 minutes for the whole journey, what was the total distance walked ?
Elementary MathematicsTime, Speed and Distance
- A4 km
- B8 km
- C16 km
- D20 km
Explanation
Let each-way distance be d: d/12+d/8 = 50/60 h. So d(5/24) = 5/6, giving d = 4 km. The whole journey (to and fro) is 8 km. Hence option (B) 8 km. (Trap: 4 km is only one way.)