Jeff Co. prepares monthly income statements. Inventory is counted only at year end; thus, month-end inventories must be estimated. All sales are made on account. The rate of mark-up on cost is 20%. The following information relates to the month of May.

Accounts receivable, May 1 $21,000

Accounts receivable, May 31 15,000

Collections of accounts during May 90,000

Inventory, May 1 45,000

Purchases during May 58,000

Calculate the estimated cost of the inventory on May 31. Show your work/calculations.