A speedboat moves at 20 km/hr in still water, and the river flows at 4 km/hr. How far can the speedboat go upstream in 45 minutes?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 12 km
Upstream the river’s speed is taken away, and the minutes must be changed to hours before multiplying by a speed in km/hr.
Upstream speed \(=20-4=16\) km/hr
Time \(\displaystyle =45\text{ min}=\frac{45}{60}=\frac{3}{4}\) hr
Distance \(\displaystyle =16\times\frac{3}{4}=12\) km