A boat can go 9 km downstream and 4 km upstream in \(2\frac{1}{2}\) hours. It can go 15 km downstream and 6 km upstream in 4 hours. How much time will it take to go 8 km downstream and 10 km upstream?
1
4 hours 10 minutes
2
3 hours 50 minutes
3
3 hours 30 minutes
4
3 hours