A trained covered x km at 40 kmph and another 2x km at 20 kmph. Find the average speed of the train in covering the entire 3x km.
Choose the correct choice from the following: A) 24 kmph B) 22 kmph C) 21 kmph D) 28 kmph E) 29 kmph
24 kmph   24 kmph   Total time taken = x/40 + 2x/20 hours   = 5x/40 = x/8 hours   24 kmphverage speed = 3x/(x/8) = 24 kmph
<result>A</result>
A trained covered x km at 40 kmph and another 2x km at 20 kmph. Find the average speed of the train in covering the entire 3x km.