Anna and Kati are celebrating their birthdays today. Three years from now, Anna will be four times as old as Kati was when Anna was two years older than Kati is now. How old is Anna if Kati is currently in high school?
Let Anna's current age be denoted by $A$, and Kati's by $K$, so their age difference is $A-K$. (This is positive, as the problem states that there was a time when Anna was two years older than Kati is now.) Thus, when Anna was $K+2$ years old, Kati was $(A-K)$ years younger, so she was $2K-A+2$ years old. According to the condition, in three years, Anna will be four times as old;

\[
A+3=4(2K-A+2)
\]

after rearranging,

\[
A=K+1+\frac{3}{5}K
\]

Since $A$ and $K$ are integers, $K$ must be divisible by 5. Assuming that the age of the high school students is between 14 and 19 years, $K=15$. Thus, $A=15+1+\frac{3 \cdot 15}{5}=25$, meaning Anna is 25 years old. It can be easily verified that the obtained results satisfy the conditions of the problem.