3. From cities $A$ and $B$, which are $250 \mathrm{~km}$ apart, two motorcyclists set off towards each other at the same time. The speed of one of them is $10 \mathrm{~km} / \mathrm{h}$ greater than the speed of the other. After two hours of travel, they still had $30 \mathrm{~km}$ left to meet. Determine the speed of each motorcyclist.
Solution. Let the speed of the first motorcyclist be $v \mathrm{~km} / \mathrm{h}$. Then the second one moves with a speed of $(v-10) \mathrm{km} / \mathrm{h}$. Now we have

$$
2 v+2(v-10)=220, \text { i.e. } v=60 \mathrm{~km} / \mathrm{h}
$$