In how many hours will two pedestrians find themselves at a distance of 32 km from each other if they leave

In how many hours will two pedestrians find themselves at a distance of 32 km from each other if they leave the same point at the same time and go in opposite directions, the first at a speed of 3 km / h and the second at a speed of 5 km / h?

Answer: in 4 hours.
Let us first find the total speed of two pedestrians, that is, the distance that they travel together in 1 hour:
3 + 5 = 8 km / h – this is how much two pedestrians will pass together in 1 hour;
And the entire distance is 32 km, which means:
32: 8 = 4 hours – after this time, two pedestrians will be at a distance of 32 km from each other.