ive already completed E6-2 this is just for reference i need help with E6-4

E62 Elmos Music carries a large inventory of guitars and other musical instruments. The store uses the FIFO method and a perpetual inventory system. Company records indicate the following for a particular line of guitars that sell for $1,600 each:

E6-4: E64 Refer to the Elmos Music inventory data in E62, except assume that the store uses the moving-weighted-average-cost method. Prepare Elmos Music Stores perpetual inventory record for the guitars on the moving-weighted-average-cost basis. Round average cost per unit to the nearest cent and all other amounts to the nearest dollar.

\begin{tabular}{rrlcc} \multicolumn{2}{c}{ Date } & Item & Quantity & Unit Cost \\ \hline May & 1 & Balance & 5 & $900 \\ & 6 & Sale & 3 & \\ 8 & Purchase & 10 & 840 \\ 17 & Sale & 4 & \\ 30 & Purchase & 5 & 840 \end{tabular}