A boatman can row 96 km downstream in 8 hr. If the speed of the current is 4 km/hr, then find in what time he will be able to cover 8 km upstream ? Choose the correct choice from the following:
A) 3 hrs  B) 7 hrs  C) 9 hrs  D) 2 hrs  E) 6 hrs

Rationale: explanation : speed in downstream = 96 / 8 = 12 kmph speed of current = 4 km / hr speed of the boatman in still water = 12 â € “ 4 = 8 kmph speed in upstream = 8 â € “ 4 = 4 kmph time taken to cover 8 km upstream = 8 / 4 = 2 hours . answer : d
Answer: D