Tambin Inc. produces a gasoline additive that, when added to the gas tank of the average automobile, is designed to

increase gas mileage by $10\%.$ The company's controller suspects that the year$-$end dollar balances shown below in the

inventory accounts may be incorrect.

There were no finished goods inventories at the beginning of the year. The company uses the weighted$-$average method of

process costing. There is only one processing department.

A review of the company's inventory and cost records shows the following: