Ragav took a bus from home to market, that travels at 40 kmph. While walking back at 4 kmph,
halfway through, he suddenly realized he was getting late and he cycled back the remaining distance in 30 kmph. Find the average speed. Choose the most appropriate option:
A) 6.5 kmph  B) 12.0 kmph  C) 28.5 kmph  D) 18.5 kmph  E) none of these
Let the distance be 2x(one way)   Time taken by bus = 2x/40, by walking =x/4, by cycling = x/30 hours   :. Average speed = Total Distance/Total time   = 4x / x/20 + x/4 + x/30   = 4 *60 / 3+15+2   = 12.0   ANSWER:12.0 kmph
<result>B</result>
Ragav took a bus from home to market, that travels at 40 kmph. While walking back at 4 kmph,
halfway through, he suddenly realized he was getting late and he cycled back the remaining distance in 30 kmph. Find the average speed.