Question

A man leaves his home and walks at a speed of 12 km per hour, reaching the railway station 10 minutes after the train had departed. If instead he had walked at a speed of 15 km per hour, he would have reached the station 10 minutes before the train's departure. The distance (in km) from his home to the railway station is

• A. 26
• B. 18
• C. 16
• D. 20

Answer 1

The Correct Option is D

In the second case, the speed is \(\frac{5}{4}\) times the speed in the first case. 
Consequently, the time would be \(\frac{4}{5}\) times the time, which is equivalent to being \(\frac{1}{5}\) less. This one-fifth is 20 minutes. 
Therefore, the time taken in the first case is 100 minutes.
The distance \(=12\times\frac{5}{3}\ km=20\ km\)