A train travels from New York to Chicago, a distance of approximately 270 miles, at an average rate of 30 miles per hour and arrives in Chicago at 6:00 in evening, Chicago time. At what hour in the morning, New York time, did the train depart for Chicago? (Note : Chicago time is one hour earlier than New York time)
Select the correct option:
A) 3:00  B) 4:00  C) 10:00  D) 6:00  E) 7:00
6:00 in evening in Chicago = 7:00 in evening in New York. So, the train was in Chicago 7:00 in the evening, New York time.   The trip took T=D/R=270/30= 
<gadget id="calculator">270/30</gadget>
<output>9</output>
9 hours. Therefore, the train depart from New York at 7:00 - 9 hours= 10:00 in the morning, New York time.   Answer: 10:00.
<result>C</result>
A train travels from New York to Chicago, a distance of approximately 270 miles, at an average rate of 30 miles per hour and arrives in Chicago at 6:00 in evening, Chicago time. At what hour in the morning, New York time, did the train depart for Chicago? (Note : Chicago time is one hour earlier than New York time)