Compute the Missing Amounts for the Statement of Earnings for Each

Compute the missing amounts for the statement of earnings for each independent case. $\begin{array}{|l|r|r|r|}\hline&\text { Case A } & \text { Case B } & \text { Case C } \\\hline \text { Sales revenue } & \$ 800 & \$ 800 & \\\hline \text { Beginning inventory } & 100 & &90 \\\hline \text { Purchases } & 500 & 420 & \\\hline \text { Total available for sale } & & & \\\hline \text { Ending inventory } & 150 & 110 & 160 \\\hline \text { Cost of goods sold } & & & 340\\\hline \text { Gross margin } & \\\hline \text { Expenses } &300 & 400 & 420 \\\hline \text { Profit } & & (50) & 60 \\\hline\end{array}$