I need help with FIFO and LIFO accounting methods please! Please EXPLAIN how you got your answer! I want to understand how to do these not just get the answer!

Refer to the first question's data to help solve the other ones. Thank you!

QUESTION 4 Use the following information for questions 4-7. Heisman Inc. uses the periodic inventory system. June 1 5 On hand, 50 units @ $15.00 each Purchased 115 units @ $15.10 each Purchased 75 units @ $15.20 each Total cost of goods available for sale On hand, 90 units $ 750.00 1,736.50 1,140.00 $3,626.50 14 30 If Heisman the FIFO inventory method, the amount assigned to the June 30 inventory would be A. $1,354.00 B. $1,366.50 C. $1,590.42 D. $1,594.00 QUESTION 5 If Heisman uses the LIFO inventory method, the cost of goods sold for June would be A. $1,354.00 B. $2,200.00 c. $2,272.50 D. $2,296.08 QUESTION 6 If Heisman uses the weighted average cost inventory method, the amount assigned to the June 30th inventory would be O A. $1,359.90 OB. $1,486.50 OC. $1,549.00 OD. $1,591.50 QUESTION 7 If the June 30th inventory included 45 units from the June 5th purchase and 45 units from the June 14th purchase, Heisman's cost of goods sold for June under the specific identification method would be OA. $2,263.00 OB. $2.373.00 OC. $2,945.00 OD. $3,626.50