What is the sum of the $x$-intercept of the line with equation $20 x+16 y-40=0$ and the $y$-intercept of the line with equation $20 x+16 y-64=0$ ?
To find the $x$-intercept of the line with equation $20 x+16 y-40=0$, we set $y=0$ and get $20 x-40=0$ or $x=2$.

To find the $y$-intercept of the line with equation $20 x+16 y-64=0$, we set $x=0$ and get $16 y-64=0$ or $y=4$.

The sum of the intercepts is $2+4=6$.