A man travels a certain distance at 15km/h and returns to the starting point at 6km/h.  The total time taken by him for the entire journey is 5\(\frac{1}{4}\) hours.  The total distance (in km.) covered by him:

45

When distance is same, then speed ∝ \(\frac{1}{time}\)

                     Go          Come

Speed   =       15     :      6 

Time     =        6       :     15

Total time ⇒ 6 + 15 = 21

                                   ⇓×\(\frac{1}{4}\)

                                  \(\frac{21}{4}\) (given)

Therefore, time taken to go = 6 × \(\frac{1}{4}\)  = \(\frac{6}{4}\) 

Total Distance = 15km/hr × \(\frac{6}{4}\) × 2 = 45 km.