Please help me solve these LIFO and FIFO questions

The Devlin Corporation, a diversified distribution company, purchases cartons of canned tennis balls from the Questor Company and markets the balls under the Devlin brand name. Devlin started operations on January 1, 2011. In the table below. Quarter 1 represents the time period from January 1, 2011 to March 31, 2011 and Quarter 2 represents the time period from April 1, 2011 to June 30, 2011. Devlin began operations on January 1, 2011 with no inventory. Purchases and sales data for Devlin's first two quarters of business are shown below