7. $A$ and $B$ are different two-digit numbers, the last digits of which are the same. It is known that the quotient of the division of $A$ by nine is equal to the remainder of the division of $B$ by nine, and the quotient of the division of $B$ by nine is equal to the remainder of the division of $A$ by nine. Find all such pairs of numbers $A$ and $B$.
82.7. Answer. $(85,75),(25,65),(15,55)$.