Question

A bus covers a certain distance in $3$ hours and $20$ minutes at an average speed of $45$$km/h$ . How long will it take to cover the same distance of a speed of $36$ $km/h$

Answer 1

Given Speed$=45km/hr$ and time$=3$ hr $20$min$=3\frac{1}{3}$ hours
Since, we have speed$=\frac{\text{Distance}}{\text{Time}}$ .......(i)
$\Rightarrow$ Distance$=$speed $\times$ time.
Distance travelled in $3\frac{1}{3}$ hr $=45\times \left(3\frac{1}{3}\right)$
$=45\times \frac{10}{3}$
$=15\times 10$
$=150$
Thus, the distance travelled in $3$ hr $20$ min is $150km$
Now, time required to cover the distance of $150km$ with the speed of $36km/hr$ is $=\frac{\text{Distance}}{\text{Speed}}$ (from equation (i))
$=\frac{150}{36}$
$=4\frac{6}{36}$
$=4\frac{1}{6}$
$=4$ hr $10$ min (since $\frac{1}{6}$ hr$=10$ min)
Therefore, required time is $=4$ hr $10$ min.