The Following Is Selected Balance Sheet and Income Statement Information

The following is selected balance sheet and income statement information for Mario Company.
$\begin{array}{|c|c|c|c|c|c|c|}\hline & \begin{array}{l}\text { Current } \\\text { Assets }\end{array} & \begin{array}{c}\text { Gross Profit } \\\text { on Sales }\end{array} & \begin{array}{l}\text { Net } \\\text { Sales }\end{array} & \begin{array}{c}\text { Net } \\\text { Income }\end{array} & \begin{array}{c}\text { Average } \\\text { Total Assets }\end{array} & \begin{array}{l}\text { Average Common } \\\text { Stockholders' Equity }\end{array} \\\hline 81 & \$ 48,06 & \$ 200,680 & \$ 450,009 & \$ 45,216 & \$ 273,710 & \$ 151,668 \\\hline\end{array}$
Compute the following ratios:
a. Gross profit percentage
b. Return on sales
c. Asset turnover
d. Return on assets
e. Return on common stockholders' equity (Mario Company has no preferred stock)