By boat, the distance between the two marinas can be covered in 12 minutes at a speed of 50 km / h.

By boat, the distance between the two marinas can be covered in 12 minutes at a speed of 50 km / h. By boat, the same distance can be covered in 2 hours. Find the speed of the boat. If x is the boat speed (in km / h), then what proportion corresponds to the condition of the problem?

Since all measurements should be comparable, let’s translate 12 minutes into hours:

1 h = 60 min.

12 minutes = 12/60 = 0.2 hours.

If we solve the problem through the proportion, then if the speed of the boat is x km / h, and the speed of the boat is 50 km / h, the ratio of their speeds will be inversely proportional to the ratio of the time during which they traveled this distance:

x / 50 = 0.2 / 2;

x = 50 * 0.2 / 2 = 5 km / h.

Answer: boat speed is 5 km / h.

Let’s check our answer by solving the problem in the usual way. The distance between the marinas is:

s = v * t = 0.2 * 50 = 10 km.

Boat speed is defined as:

v = s / t = 10/2 = 5 km / h.