The boat traveled along the river in 3 hours the same distance as it travels in 3 hours and 36 minutes against the current.

The boat traveled along the river in 3 hours the same distance as it travels in 3 hours and 36 minutes against the current. If the speed of the river is 3 km / h, then the boat’s own speed is …

1. We translate minutes into hours:

3 hours 36 minutes = 3 and 36/60 hours = 3.6 hours.

2. Take the speed of the boat in still water (own speed) as x (km / h).

3. Down the river the boat sailed at a speed of (x + 3 km / h, in the opposite direction it sailed at a speed of (x – 3) km / h.

4. Considering that the boat sailed down the river, as many kilometers as in the opposite direction, we compose the equation:

3 (x + 3) = 3.6 (x – 3);

3x + 9 = 3.6x – 10.8;

0.6x = 19.8;

x = 33 km / h.

Answer: the speed of the boat in still water is 33 km / h.