The speed of a train including stoppages is 90 kmph and excluding stoppages is 120 kmph. Of how many minutes does the train stop per hour?  Choose the correct choice from the following.
A) 9
B) 10
C) 12
D) 14
E) 15
15xplanation:   T = 30/120 * 60= 
<gadget id="calculator">30/120 * 60</gadget>
<output>15</output>
15   Answer: Option 15
<result>E</result>
The speed of a train including stoppages is 90 kmph and excluding stoppages is 120 kmph. Of how many minutes does the train stop per hour?