Pawan travels from X to Y at the speed of 10 km/h, from Y to Z at 15 km/h and from Z to W at 20 km/h. If XY = YZ = ZW (in km), then the average speed of Pawan for the whole journey is:

$13\frac{11}{13}$ km/h

Given :-

Let XY = YZ = ZW = 60 km

Time for XY = \(\frac{60}{10}\) = 6 hours

Time for YZ = \(\frac{60}{15}\) = 4 hours

Time for ZW = \(\frac{60}{20}\) = 3 hours

Average Speed = \(\frac{60 + 60 + 60}{6 + 4 + 3}\)  = \(\frac{180}{13}\)

= 13\(\frac{11}{13}\) km/h