Assuming a perpetual inventory system and using the first$-$in$,$ first$-$out $($FIFO$)$ method, determine $($a$)$ the cost of the goods sold on October $24$ and $($b$)$ the value of inventory on hand on October $31.$

a$.$ Cost of the goods sold on October $24$

$

b$.$ Inventory value on October $31$

$