City A and City B are 140 miles apart. Train C departs City A, heading towards City B, at 4:00 and travels at 40 miles per hour. Train D departs City B, heading towards City A, at 5:30 and travels at 20 miles per hour. The trains travel on parallel tracks. At what time do the two trains meet?
Choose the most appropriate option.
A) 5:00
B) 7:30
C) 6:00
D) 6:30
E) 7:00
Train C has traveled 20 mi in the half hour before Train D has started its journey.   140-20= 
<gadget id="calculator">140-20</gadget>
<output>120</output>
120   40+20= 
<gadget id="calculator">40+20</gadget>
<output>60</output>
60 mph   120 mi/ 60 mph= 2 hrs   5:30pm + 2 hrs = 7:30pm   Answer:   B. 7:30
<result>B</result>
City A and City B are 140 miles apart. Train C departs City A, heading towards City B, at 4:00 and travels at 40 miles per hour. Train D departs City B, heading towards City A, at 5:30 and travels at 20 miles per hour. The trains travel on parallel tracks. At what time do the two trains meet?