When Mary Potts arrived at her store on the morning of January 29, she found empty shelves and display racks; thieves had broken in during the night and stolen the entire inventory. Accounting records showed that Potts had inventory costing $51,000 on January 1. From January 1 to January 28, Potts had made net sales of $71,400 and net purchases of $81,600. The gross profit during the past several years had consistently averaged 43 percent of net sales. Potts plans to file an insurance claim for the theft loss.

a. Using the gross profit method, estimate the cost of inventory at the time of the theft.