smc

Let $C$ represent the cost of the goods, and let $L$, $S$, and $M$ represent the list, selling, and marked prices of the goods, respectively. Hence, we have three equations, which we need to manipulate in order to relate $M$ and $L$: $C=\frac{4}{5}L$ $S=C+\frac{1}{5}S$ $S=\frac{4}{5}M$ We find that $M=\frac{5}{4}L$. Hence, the percent of the list price which should be marked is $\boxed{125}$.