Question

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

• A. $9$
• B. $10$
• C. $12$
• D. $20$

Answer 1

The correct option is B

$10$

Explanation for the correct option:

Finding for how much time did the bus stop per hour:

Given that excluding stoppages, the speed of a bus is $54$ kmph.

Distance travelled by bus in one hour, excluding stoppages $=54$ km.

Including stoppages the speed of the bus is $45$km/hr.

Distance travelled by the bus in one hour, including stoppages $=45$ km.

Distance travelled by bus in one hour excluding stoppages $–$ distance travelled by bus in one hour including stoppages $=54-45=9$km

Time taken to cover$9$ km $=$ $\frac{dis\tan ce}{speed}$

Usual speed of the bus $=54$ km/hour

Time to cover $9$ km $=\frac{9}{54}$

Time taken in minutes $=\frac{9}{54}\times 60$

$=10$ minutes

Hence, option$B$ is the answer.