Three Identical Units of Merchandise Were Purchased During July, as Follows

Three identical units of merchandise were purchased during July, as follows:? $$\begin{array} { | l | c | c | r | } \hline \text { Date } & \text { Product Basic H } & \text { Units } & { \text { Cost } } \\\hline \text { July } 3 & \text { Purchase } & 1 & \$ 35 \\\hline 10 & \text { Purchase } & 1 & 36 \\\hline 24 & \text { Purchase } & 1 & 37 \\\hline \text { Total } & & \mathbf { 3 } & \mathbf { \$ 1 0 8 } \\\hline & & & \\\hline & \text { Average cost per unit } & & \$ 36 \\\hline\end{array}$$ Assume one unit sells on July 28 for $45.Determine the gross profit, cost of merchandise sold, and ending inventory on July 31 using the
(a) first-in, first-out,
(b) last-in, first-out, and
(c) average cost flow methods.