Two tourists left at the same time to meet each other from points, the distance between which is 18 km.

Two tourists left at the same time to meet each other from points, the distance between which is 18 km. One of them runs an average of 4 km per hour, and the second 5 km. In how many hours will they meet?

Let’s take x time before the meeting, then
4 * x- distance covered by the first tourist,
5 * x – the distance traveled by the second.
Since the total distance is 18 km and is equal to the sum of the distances traveled separately, we get the equation:
4 * x + 5 * x = 18
x * (4 + 5) = 18
x * 9 = 18
x = 18/9 = 2 hours.