A boat can row at the speed of 16 km/hr in still water. If the river is flowing at 8 km/hr, and it takes 8 hours for a round trip, then the distance between the two places is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 48 km
With the current the boat moves faster, against it slower:
\(\text{Downstream speed} = 16 + 8 = 24 \text{ km/hr}\)
\(\text{Upstream speed} = 16 - 8 = 8 \text{ km/hr}\)
Let the distance be d km. The total time for going down and coming back is 8 hours:
\( \displaystyle \frac{d}{24} + \frac{d}{8} = 8 \)
\( \displaystyle \frac{d + 3d}{24} = 8 \)
\(4d = 192\)
\(d = 48\)
So the two places are 48 km apart.