The length of the reservoir is 200 km more than its width. A trip on a boat with the same speed along its length takes 30 hours

The length of the reservoir is 200 km more than its width. A trip on a boat with the same speed along its length takes 30 hours, width 20 hours. Find the length and width of this reservoir.

Let’s determine the speed of the boat. To do this, you need to find the difference in time when it floats in length and width:
30 – 20 = 10 hours
During this time, he swims 200 km, the speed is calculated by the formula:
V = S: t = 200: 10 = 20 km / h.
Let’s calculate the length of the reservoir that the boat can cover in 30 hours. Let’s find the paths by the formula:
S = V * t = 20 * 30 = 600 km.
Width – for 20 hours, therefore it is equal to:
20 * 20 = 400 km.