A train is moving at 6/7 of its usual speed. The train is 30 minutes too late. What is the usual time for the train to complete the journey?	Choose one.
A) 1 hour	B) 30 minutes	C) 3 hours	D) 2 hours 30 min	E) 2 hours
new time = d / (6v/7) = 7/6 * usual time   30 minutes represents 1/6 of the usual time.   The usual time is 3 hours.   The answer is 3 hours.
<result>C</result>
A train is moving at 6/7 of its usual speed. The train is 30 minutes too late. What is the usual time for the train to complete the journey?