Calvin had 1/2 as much money as Eddy. Calvin spent $36 and Eddy had 8 times as much money as Calvin in the end. How much did both of them have altogether at first?
$c=\frac12 e$, $8(c-36)=e$. Now solve for $e+c$.
$c=1/2e$(c is calvin's money at the start, e is eddy's money at the start)