If a student walks from his home to school at the speed of 2.5 km/hr, he gets late by 6 min and if he increases his speed by 1 km/hr, he reaches 6 min earlier. Find the distance between his home and school.

1.75 km

Distance is same, therefore speed is inversely proportional to time.

                  I               II

Speed      2.5     :     3.5

                  5      :      7

Time          7       :     5   →   2 (Difference)

                                2   →   12 (6 mins early + 6 mins late) 

                                1   →   6 mins = \(\frac{6}{60}\) hr = \(\frac{1}{10}\) hr.

Therefore,  Distance =  speed × time = 2.5 × 7 × \(\frac{1}{10}\) = 1.75 Km