Average Practice Test 3

Let the total distance covered during journey = 60 km
$\frac{1}{3}$ 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 km
Time taken to cover 20 km at 25 km/h $=\frac{20}{25}$hours $=\frac{4}{5}$ hour
Time taken to cover 15 km at 30 km/h $=\frac{15}{30}$hours $=\frac{1}{2}$ hour
Time taken to cover 25 km at 50 km/h $=\frac{25}{50}$ hours $=\frac{1}{2}$ hour
Total time taken $=\frac{4}{5}+\frac{1}{2}+\frac{1}{2}=\frac{9}{5}$ hours
Hence average speed per hour $=\frac{60÷9}{5}=60\times \frac{5}{9}=\frac{100}{3}$km / h
= $33\frac{1}{3}$km