Average Practice Test 3

Let the total distance covered during journey = 60 km$rac{1}{3}$ of the distance covered during journey $= 60 \times \frac{1}{3}$= 20 km$\frac{1}{4}$ of the distance covered during journey $= \frac{1}{4} \times 60$ = 15 km∴ The distance covered during the rest of journey = 60 – (20 + 15) = 25 kmTime taken to cover 20 km at 25 km/h $= \frac{20}{25}$hours $= \frac{4}{5}$ hourTime taken to cover 15 km at 30 km/h $= \frac{15}{30}$hours $= \frac{1}{2}$ hourTime taken to cover 25 km at 50 km/h $= \frac{25}{50}$ hours $= \frac{1}{2}$ hourTotal time taken $= \frac{4}{5} + \frac{1}{2} + \frac{1}{2} = \frac{9}{5}$ hours Hence average speed per hour $= 60 \div \frac{9}{5} = 60 \times \frac{5}{9} = \frac{100}{3}$km / h = $33 \frac{1}{3}$km