Moderate Time, Speed & Distance Solved QuestionAptitude Discussion

 Q. A bus without stopping travels at an average speed of 60 km/hr and with stoppages at an average speed of 40 km/hr. What is the total time taken by the bus for stoppages on a route of length 300km?
 ✖ A. 4 hr ✖ B. 3 hr ✔ C. 2.5 hr ✖ D. 3.5 hr

Solution:
Option(C) is correct

Let $r$ = running time of the train

$s$= stoppage time of the train

$D$= total distance travelled by train

We have:

$\dfrac{D}{r}=60\text{ and }\dfrac{D}{r+s}=40$

$\Rightarrow \dfrac{r+s}{r}=\dfrac{3}{2}$

$\Rightarrow \dfrac{s}{r}=\dfrac{1}{2}$

As, $D=300$ kms

$\dfrac{300}{r}=60$

$⇒ r=5$ hrs and $s$ = 2.5 hr

Edit: For an alternative solution, check comment by Zoha Amjad.

(2) Comment(s)

Achin
()

ShortCut:

Time taken by bus to go nonstop=300/60=5Hr

Time taken by bus to go with stoppages=300/40=7.5Hr

Extra time =7.5-5.0=2.5

Bus takes 2.5 hours for stoppages.

$t= \dfrac{300}{60} = 5$ hrs
$t= \dfrac{300}{40} = 7.5$
$=7.5-5 = \textbf{2.5 hrs}$