Question

A man travelled a distance of 60 km in 7 hours. He travelled partly on foot at the speed of 6 km/h and partly on cycle at the speed of 12 km/h. What is the distance travelled on foot (in km)?
1. 48 km
2. 24 km
3. 9 km
4. 12 km

Answer 1

Correct Answer - Option 2 : 24 km

Given:

Total distance = 60 km

Time taken = 7 hours

Formula used:

Speed = Distance travelled/Time taken

Calculation:

Let the distance travelled on foot be D km and time taken to be T hour.

Then, The speed of man on foot = D/T

⇒ 6 = D/T      ----(1)

The speed of man on cycle = (60 - D)/(7 - T)

⇒ 12 = (60 - D)/(7 - T)

⇒ 12 × (7 - T) = (60 - D)

⇒ 84 - 12T = 60 - D      ----(2)

Put the value of D = 6T from equation (1) in equation (2), we get

⇒ 84 - 60 = 12T - 6T

⇒ 24 = 6T

⇒ T = 4 hours

Distance travelled on foot = 6 × 4 = 24 km

∴ Distance travelled on foot is 24 km.