HELP!! Perpetual inventory using FIFO

Beginning inventory, purchases, and sales for Item Zeta $9$ are as follows:

$\backslash$table$[[$Oct$.1$ Inventory,$62$ units @ $$18],[$Oct$.7$ Sale,$46$ units$],[$Oct$.15$ Purchase,$45$ units @ $$21],[$Oct$.24$ Sale,$24$ units$]]$

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

b$.$ Inventory on October $31x$