The speed of a bus including stoppages is 35 kmph and excluding stoppages is 70 kmph. Of how many minutes does the train stop per hour?	Choose the correct choice:
A) 7
B) 15
C) 25
D) 30
E) 35
Explanation:   T = 35/70 * 60= 
<gadget id="calculator">35/70 * 60</gadget>
<output>30</output>
30   Answer: Option 30
<result>D</result>
The speed of a bus including stoppages is 35 kmph and excluding stoppages is 70 kmph. Of how many minutes does the train stop per hour?