A man divided his journey into three parts of distances of 18 km, 20 km and 27 km. He travelled the distances at the speeds of 6 km/h, 5 km/h and 9 kn/h,respectively. What was his average speed during the entire journey?

6.5 km/h

Given :-

Time 1 = \(\frac{18}{6}\) = 3 hours

Time 2 = \(\frac{20}{5}\) = 4 hours

Time for 3 = \(\frac{27}{9}\) = 3 hours

Average Speed = \(\frac{18 + 20 + 27}{3 + 4 + 3}\)  = \(\frac{65}{10}\)

= 6.5 km/h