10. Aunt Masha is three years younger than Sasha and his same-aged friend Pasha combined. How old is Sasha when Aunt Masha was as old as Pasha is now?
10. Let Sasha and Pasha be $a$ years old, then Aunt Masha is $(2 a-3)$ years old. Aunt Masha was $a$ years old $(a-3)$ years ago $(2 a-3-a=a-3)$. But so many years ago, Sasha was 3 years old $(a-(a-3)=3)$.