Stamp exchange minimum

Luke and Laco exchanged stamps. Before the exchange, Luke had 25 more marks than Laco. After the exchange, he had more Laco marks. At least how many stamps does Laco receive from Luke?

Final Answer:

x =  13

Step-by-step explanation:

$$\begin{gathered} x=(25+1)/2=13 \\ \text{ Verifying Solution: } \\ a=50+25=75 \\ b=50 \\ {a}_2=a-x=75-13=62 \\ {b}_2=b+x=50+13=63 \end{gathered}$$

Try another example