Question

Excluding stoppages, the speed of a bus is 54 km per hour and including stoppages, it is 45 km per hour. For how many minutes does the bus stop per hour?

Answer 1

Hint: Here we will proceed by calculating the loss in speed including stoppages and excluding stoppages. Then by using the formula of time i.e., we will find the time the bus stops per hour. $\dfrac{{Distance}}{{speed}}$

Complete step-by-step solution -
As we are given that-
Speed of the bus excluding stoppages = 54 km per hour
And Speed of the bus including stoppages = 45 km per hour
Loss in speed when including stoppages = 54 – 45 = 9 km per hour.
So we get-
In 1 hour, the bus covers 9 km less due to stoppages.
Hence time in which the bus stops per hour = Time taken to cover 9 km
Now we will use formula of time $ = \dfrac{{Distance}}{{speed}}$
Time taken to cover 9 km $ = \dfrac{9}{{54}}hour$
$\Rightarrow \dfrac{1}{6}hour$
$\Rightarrow \dfrac{{60}}{6}\operatorname{minutes} $
$\Rightarrow 10$ minutes
Hence the time in which the bus stops per hour is 10 minutes.

Note: In order to solve this type of question, we can also use another way like we will find the LCM of both the speed of the bus including stoppages and excluding stoppages. Then we can use the formula of time to calculate the time when the bus stops per hour.