The inventory records for Radford Company reflected the following:

Beginning inventory @ May 1

First purchase @ May 7

Second purchase @ May 17

Third purchase @ May 23

Sales @ May 31

1,600 units @ $4.80

1,700 units @ $5.00

1,900 units @ $5.10

1,500 units @ $5.20

5,200 units @ $6.70

What is the amount of gross margin assuming the FIFO cost flow method?