The two boats were moving at the same speed. the first boat sailed 120 km, and the second -135 km.

The two boats were moving at the same speed. the first boat sailed 120 km, and the second -135 km. At what speed did each boat move if the first of them was on the way 30 minutes less than the second?

Since the speed of the boats is the same, we will take it as x, then:

120: x = 120 / x – travel time of the first boat;

135: x = 135 / x – time of the second.

We get the equation (30 minutes = 1/2 hour):

135 / x – 120 / x = 1/2;

15 / x = 1/2;

x = 30.

Answer: the speed of the boats was 30 km / h.