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___

Answer 1

Let the distance between home and railway station be ‘d’ km.
$\frac{d}{12}–\frac{d}{15}=\frac{20}{60}d=20km$