Beginning inventory, purchases, and sales for Item Zeta$9$ are as follows: Date Line Item Description Value Oct. $1$ Inventory $60$ units at $$22$ Oct. $7$ Sale $39$ units Oct. $15$ Purchase $39$ units at $$23$ Oct. $24$ Sale$28$ units Assuming a perpetual inventory system and using the first$-$in$,$ first$-$out $($FIFO$)$ method, determine $($a$)$ the cost of goods sold on October $24$ and $($b$)$ the inventory on October $31.$ a$.$ Cost of goods sold on October $24$ fill in the blank $1$ of $2$ b$.$ Inventory on October $31$ fill in the blank $2$ of $2$