Question : A man has to be at a certain place at a certain time. He finds that he shall be 20 minutes late if he walks at 3 km/hr speed and 10 minutes earlier if he walks at a speed of 4 km/hr. The distance he has to walk is:
Option 1: 24 km
Option 2: 12.5 km
Option 3: 10 km
Option 4: 6 km
Correct Answer: 6 km
Solution :
Let
Time taken in the first case =
Time taken in the second case =
Time difference =
So,
⇒
⇒
Hence, the correct answer is 6 km.