A trained covered x km at 90 kmph and another 2x km at 20 kmph. Find the average speed of the train in covering the entire 3x km. Choose the most appropriate option:
A) 22	B) 99	C) 27	D) 66	E) 887

Rationale: total time taken = x / 90 + 2 x / 20 hours = x / 9 hours average speed = 3 x / ( x / 9 ) = 27 kmph answer : c
Answer: C