фuin A.

Two people were walking towards each other along a straight path at constant speeds, but one was slow, the other was fast. At the same time, each let a dog run ahead of them (the dogs ran at the same constant speed). Each dog ran to the other owner and returned to its own. Whose dog returned earlier - the fast owner's or the slow owner's?
Let $L$ be the distance between the people at the moment they released the dogs, $v$ and $V > v$ be the speeds of the people, and $u$ be the speed of the dogs. The dog of the slower person will reach the faster person in $\frac{L}{u+V}$ time, and during this time, it will have moved away from its owner by a distance of $\frac{L(u-v)}{u+V}$. It will return to its owner in $\frac{L(u-v)}{(u+V)(u+v)}$ time. The total time of its "journey" is $\frac{L}{u+V} + \frac{L(u-v)}{(u+V)(u+v)} = \frac{2 L u}{(u+V)(u+v)}$. The same result can be obtained analogously for the other dog.

## Answer

The dogs returned simultaneously.