Let's denote the amount to be paid annually by $x$. According to the problem,

$$
\left(x+x \frac{2.5}{100}\right)+\left(x+x \frac{5}{100}\right)+x=6300
$$

or

$$
3 x+\frac{15}{100} x=6300
$$

from which

$$
x=2000 \text{ K}
$$

(Borota Braniszláv, Szeged.)
Valakinek 3 év múlva kamatok nélkül $6300 \mathrm{~K}-\mathrm{t}$ kellene fizetnie. Mennyit kellene e helyett 3 éven át minden év végén fizetnie, ha $1 \%$-os kamatmegtérítéshen részesül?

Someone should pay $6300 \mathrm{~K}-\mathrm{t}$ without interest in 3 years. How much should they pay instead at the end of each year over 3 years if they receive a $1 \%$ return on investment?