Perpetual Inventory Using LIFO

Beginning inventory, purchases, and sales for Item ER$27$ are as follows:

$\backslash$table$[[$October $1,$Inventory,$106$ units @ $$29],[5,$Sale,$85$ units$],[11,$Purchase,$118$ units @ $$33],[21,$Sale,$99$ units$]]$

Assuming a perpetual inventory system and using the last$-$in$,$ first$-$out $($LIFO$)$ method, determine $($a$)$ the cost of merchandise sold on October $21$ and $($b$)$ the inventory on October $31.$

a$.$ Cost of merchandise sold on October $21$

b$.$ Inventory on October $31$