Q$-1-$From the given information, calculate the cost of inventory as well as the cost of goods sold using the $($a$)$ specific invoice, $($b$)$ weighted$-$average, $($c$)$ first$-$in$,$ first$-$out, and $($d$)$ last$-$in$,$ first$-$out methods.

$\backslash$table$[[,$Goods Available for Sale,Additional Fact: Inventory Not Sold$],[$Units$,,$Cost,Total$],[$January $1$ Beg. Inventory,$40,$@$,$$ $8,=,$$$,320,40$ from January $1],[$April $1$ Purchased,$20,$@$,9,=,,180,],[$May $1$ Purchased,$20,$@$,10,=,,200,4$ from May $1],[$October $1$ Purchased,$20,$@$,12,=,,240,4$ from October $1],[$December $1$ Purchased,$20,$@$,13,=,,260,],[,{120}_{{?}_{?}},,,,,1,200,]]$