Answer:
A=65, B=40
Explanation:
The problem can be rewritten by using the following equations:

where the second equation means "A:B is equivalent to 13:8".
The second equation can be rewritten as:

Which means

Substituting this into the first equation, we get

And by susbtituting B=40 into the first equation, we find

So, the solution is
A=65
B=40