In the right triangle $\triangle ACE$, we have $AC=12$, $CE=16$, and $EA=20$. Points $B$, $D$, and $F$ are located on $AC$, $CE$, and $EA$, respectively, so that $AB=3$, $CD=4$, and $EF=5$. Find the ratio of the area of $\triangle DBF$ to that of $\triangle ACE$. The answer is in the form \frac{k}{m}, please provide the value of k + m.

Let's think step by step and output the final answer within \boxed{}.
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