Speed of Sailboat in Still Water Calculation

What is the speed of the sailboat in still water?

Charles went on a sailing trip 30 kilometers each way. The trip against the current took 5 hours. The return trip with the assistance of the current took only 3 hours. Find the speed of the sailboat in still water.

Answer:

The speed of the sailboat in still water is 8 km/h.

To find the speed of the sailboat in still water, we can use the formula: Speed of boat in still water = (Speed against current + Speed with current)/2. Let's assume the speed of the current is c and the speed of the sailboat in still water is s. Given that the trip against the current took 5 hours and the return trip with the assistance of the current took 3 hours, we can set up the following equations:

30/(s - c) = 5 and 30/(s + c) = 3.

Solving these equations simultaneously, we find s = 8 km/h and c = 2 km/h. Therefore, the speed of the sailboat in still water is 8 km/h and the speed of the current is 2 km/h.