Question

A bus is going from Delhi to Lucknow via different routes $A\&B$ respectively as shown in the figure. If bus takes $6\text{hrs}$ via route $A$ and $8\text{hrs}$ via route $B$. Then, for which of the routes, bus has higher average speed ?

• A. In both routes the average speed of bus is same
• B. Route $A$
• C. Route $B$
• D. data insufficient

Answer 1

The correct option is C Route $B$

For route $A$, displacement and distance covered are equal.
$\Rightarrow {\text{Speed}}_{\text{Avg}}=\frac{\text{Distance covered}}{\text{Time taken}}$
$\Rightarrow {\text{Speed}}_{\text{Avg}}=\frac{480\text{km}}{6\text{hr}}$
$\Rightarrow {\text{Speed}}_{\text{Avg}}=80\text{km/hr}$
For journey through route $B$, displacement and distance covered are not equal.
$\Rightarrow {\text{Speed}}_{\text{Avg}}=\frac{\text{Distance covered}}{\text{Time taken}}$
$\Rightarrow {\text{Speed}}_{\text{Avg}}=\frac{720\text{km}}{8\text{hr}}$
$\Rightarrow {\text{Speed}}_{\text{Avg}}=90\text{km/hr}$
Hence average speed is higher in case of jouney via route $B$