Two trains leave the same train station at 6:00 am and 6:30 am and they travel at 100 kph and 120 kph respectively. How many kilometers from the train station will the two trains be together?
Options:
A) 300 B) 320 C) 340 D) 360 E) 380
At 6:30, the first train is 50 km ahead.   The second train gains 20 km each hour.   The time it takes the second train to catch the first train is 50 /20= 
<gadget id="calculator">50 /20</gadget>
<output>5/2 = around 2.5</output>
2.5 hours.   In this time, the second train travels   2.5*120= 
<gadget id="calculator">  2.5*120</gadget>
<output>300</output>
300 km.   The answer is 300.
<result>A</result>
Two trains leave the same train station at 6:00 am and 6:30 am and they travel at 100 kph and 120 kph respectively. How many kilometers from the train station will the two trains be together?