Question

The speed of a bus is $54$ km/hr excluding stoppage and $45$ km/hr including stoppages. For how many minutes does the bus stop per hour?

• A. $12$ min
• B. $10$ min
  
• C. $8$ min
  
• D. $6$ min
  

Answer 1

The correct option is B $10$ min

L.C.M. of 54 and 45 = 270
$\therefore$ Time taken by bus to cover 270 km excluding stoppages $=\frac{270}{54}=5hours$

Time taken by bus to cover 270 km including stoppages $=\frac{270}{45}=6hours$

$\therefore$ Time for which the bus stops per hour $=\frac{6-5}{6}hours=\frac{1}{6}\times 60min=10min.$