Sum of the ages

We have,

$(A-5)+(B-5)=53$ $\implies$ $A-5+B-5=53$ $\implies$ $A+B=63$

The sum of their ages $20$ years from now will be $63+20+20=\boxed{103}$

IN other words the question asks us to find the sum of ages after 25 years from the one mentioned and since both increase we will have to add twice:

$\therefore 53 + 25 (Of\ A) + 25 (Of\ B) = \color{#3D99F6} 103 \implies \text{ The answer }$