48. How old is each of us, if I am now twice as old as you were when I was as old as you are now, and we are both 63 years old in total.
48. Translating the condition of the problem into the language of algebra, we get the system:

|  | Me | You |
| :--- | :--- | :--- |
| Now | $2 x$ | $y$ |
| Then | $y$ | $x$ |

$\quad\left\{\begin{array}{c}2 x+y=63 \\ 2 x-y=y-x\end{array}\right.$. From which $x=18, y=27$. Answer: I am 36 years old, You are 27 years old,