Correct Answer - Option 3 : 63 km
Given:
Speed of boat in still water = 16 km/hr
Speed of the stream = 5 km/hr
Time = 3 hours
Formula used:
Distance = speed × Time
If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then,
Speed downstream = (u + v) km/hr
Calculation:
Speed downstream = (16 + 5) km/hr = 21 km/hr
Travelled distance = (21 × 3) km = 63 km
∴ The distance travelled downstream in 3 hours is 63 km