Question

One car moving on a straight road covers one third of the
distance with 20 km/hr and the rest with 60 km/hr. The
average speed is​

Answer 1

Explanation:

total time taken by the car

$( \frac{ \frac{1}{3} }{20} + \frac{ \frac{2}{3} }{60} )hrs \\= (\frac{1}{60} + \frac{1}{90}) hrs \\ = \frac{60 + 90}{60 \times 90} hrs \\ = \frac{150}{5400} \\ =\frac{1}{36} hrs \\ therefore \: average \: speed \: is \\= \frac{ 1 }{ \frac{1}{36} } km.h {}^{ - 1} \\ = 36 \: km.h {}^{ - 1}$