2 hours after train A leaves Lucknow a train B leaves the same stationtraveling in the same direction at an average speed of 28 km/hr. After traveling 6 hrsthe train B overtakes the train A. What is the average speed of the train A?  Pick one: A) 15 km/hr B) 16 km/hr C) 17 km/hr D) 21 km/hr E) None of these
Explanation :   Total distance covered by B=28*6= 
<gadget id="calculator">28*6</gadget>
<output>168</output>
168kmTotal time taken by A to cover same distance=2+6= 
<gadget id="calculator">2+6</gadget>
<output>8</output>
8 hrsaverage speed of A=168/8= 
<gadget id="calculator">168/8</gadget>
<output>21</output>
21 km/hr   Answer : 21 km/hr
<result>D</result>
2 hours after train A leaves Lucknow a train B leaves the same stationtraveling in the same direction at an average speed of 28 km/hr. After traveling 6 hrsthe train B overtakes the train A. What is the average speed of the train A?