A train runs with the speed of 72 km/h.  It reaches its destination late by 15 minutes.  However, if speed is 90 km/h, it is late by only 5 minutes.  The correct time (min) to cover its journey and find distance.

35, 60

Speed   ⇒    72   :   90

                    4   :    5

time     ⇒      5   :    4 ... (diff. 1 → ×10 → 10)

                    ↓

                   ×10  

                    ↓    

                 50 min   

Correct time = 50 - 15 = 35 min

D = 72 × \(\frac{50}{60}\) = 60 km