Mike took a bus from home to market, that travels at 30 kmph. While walking back at 6 kmph,
halfway through, he suddenly realized he was getting late and he cycled back the remaining distance in 20 kmph. Find the average speed.
Choose one:
A) 21.2 kmph B) 12.1 kmph C) 23.4 kmph D) 20.4 kmph E) none of these
Let the distance be 2x(one way)   Time taken by bus = 2x/30, by walking =x/6, by cycling = x/20 hours   :. 21.2 kmphverage speed = Total Distance/Total time   = 6x / x/15 + x/6 + x/20   = 6 *60 / 4+10+3   = 21.2   21.2 kmphNSWER:21.2 kmph
<result>A</result>
Mike took a bus from home to market, that travels at 30 kmph. While walking back at 6 kmph,
halfway through, he suddenly realized he was getting late and he cycled back the remaining distance in 20 kmph. Find the average speed.