There are two stationary boats (A and B) on a river. B is downstream from A. At 9AM, a raft starts floating downstream from A to B. The still water speed of the raft is 0 kmph. At the same time, a boat starts out from B to A and meets the raft in 5 hours and then reaches A. It immediately returns to B. Find the time that the boat and the raft reached B, if it is given that they both reached together?
:
C
Option ( c)
Speed of river= S kmph
Speed of boat= B kmph
In 5 hours, the boat would have traveled 5(B-S)km and the raft would have traveled 5S km
The raft has to cover 5(B-S)km at S km/hr speed
The boat has to cover 5S km at (B-S) kmph and (5S+5B-5S) km at (B+S) kmph speed
5(B−S)S=5SB−S+5BB+S
It will take 52 hours= 7.07 hours after 2 pm.
Answer = option c
Was this answer helpful ?
Submit Solution