The ratio of the speed of boat in still water to the speed of stream is 16 : 5. A boat goes 16.5 km in 45 minute upstream, find the time taken by boat to cover the distance of 21 km downstream.

• ক 30 minutes ✅ সঠিক উত্তর
• খ 25 minutes
• গ 19 minutes
• ঘ 29 minutes