Question

A car covers first $100km$ in $2\frac{1}{2}$ hours and then travels at a speed of $60km/hr$ for $1\frac{1}{2}$ hours. Find the average speed of the car for the whole journey.

Answer 1

As we know that

$\text{speed}=\frac{\text{distance}}{\text{time}}$

Distance travelled by the car in $1\frac{1}{2}$ hours when travelling with the speed of $60km/hr=60\times \frac{3}{2}=90km$

Total distance travelled by the car $=100+90=190km$

Total time taken $=\frac{5}{2}+\frac{3}{2}=4$ hours

Therefore,

Average speed $=\frac{\text{Total distance}}{\text{total time}}=\frac{190}{4}=47.5km/hr$