Crossing the River (Minimum Distance)

Q. A boat which has a speed of $5\text{km/h}$ in still water crosses a river of width $1\text{km}$ along the shortest possible path in $15\text{min}$. The velocity of the river water in $\text{km/h}$ is

1. $1$
2. $3$
3. $4$
4. $\sqrt{41}$

Q.

River is flowing at 3 Km/h in the west direction and You can swim at a maximum speed of 5 Km/h , Given if the river is 12 km wide, How long will you take to cross the river?

1. 4 hr

2. 2.4 hr

3. 3 hr

4. Data insufficient

Q. A boat moves relative to water with a velocity $u$ and river is flowing with $2u$. At what angle with the stream should the boat move to have minimum drift ?

1. ${30}^{\circ }$
2. ${60}^{\circ }$
3. ${90}^{\circ }$
4. ${120}^{\circ }$

Q. A boat which has a speed of $5\text{km/h}$ in still water crosses a river of width $1\text{km}$ along the shortest possible path in $15\text{min}$. The velocity of the river water in $\text{km/h}$ is

1. $1$
2. $3$
3. $4$
4. $\sqrt{41}$

Q. A man wishes to cross a river and come back to original position by swimming minimum distance. If the width of the river is 50 m, speed of river is 2 m/s and velocity of man with respect to river is 4 m/s, then time taken by man to come back to original position is

1. 
   $\frac{50}{\sqrt{3}}$ sec
2. 
   50$\sqrt{2}$ sec
3. 
   25 sec
4. 
   25$\sqrt{3}$ sec