2 hours after train A leaves Lucknow a train B leaves the same stationtraveling in the same direction at an average speed of 20 km/hr. After traveling 6 hrsthe train B overtakes the train A. What is the average speed of the train A?	Choose one:  A) 15 km/hr  B) 16 km/hr  C) 17 km/hr  D) 18 km/hr  E) None of these
Explanation :   Total distance covered by B=20*6= 
<gadget id="calculator">20*6</gadget>
<output>120</output>
120kmTotal time taken by 15 km/hr to cover same distance=2+6= 
<gadget id="calculator">2+6</gadget>
<output>8</output>
8 hrsaverage speed of 15 km/hr=120/8= 
<gadget id="calculator">120/8</gadget>
<output>15</output>
15 km/hr   15 km/hrnswer : 15 km/hr
<result>A</result>
2 hours after train A leaves Lucknow a train B leaves the same stationtraveling in the same direction at an average speed of 20 km/hr. After traveling 6 hrsthe train B overtakes the train A. What is the average speed of the train A?