What formula or steps do I follow to get $68,000? 13. The following information is available for October for Norton Company. A fire destroyed Nortons October 31 inventory, leaving undamaged inventory with a cost of $12,000. Using the gross profit method, the estimated ending inventory destroyed by fire is? $68,000 Beginning inventory $200,000 Net purchases 600,000 Net sales 1,200,000 Percentage markup on cost 66.67%