Problem $5-8$AA Perlodlc: Income comparisons and cost flows

QP Corp. sold $4,000$ units of its product at $$50$ per unit during the year and incurred operating expenses of $$5$ per unit in selling the units. It began the year with $700$ units in inventory and made successive purchases of its product as follows.

$\backslash$table$[[$Jan$.1,$Beginning inventory,$700$ units @$$18$ per unit$],[$Feb$.20,$Purchase,$1,700$ units & $$19$ per unit$],[$May $16,$Purchase,$800$ units @ $$20$ per unit$],[$Oct$.3,$Purchase,$500$ units @$$21$ per unit$],[$Dec $11,$Purchase,$2,300$ units ${?}_{(})$$$$22$ per unit$],[,$Total,$6,000$ units$]]$

Required

Prepare comparative year$-$end income statements for the three inventory costing methods of FIFO, LIFO, and weighted average. $($Round all amounts to cents.$)$ Include a detailed cost of goods sold section as part of each statement. The company uses a periodic inventory system.

How would the financial results from using the three alternative inventory costing methods change if the company had been experiencing declining costs in its purchases of inventory?

What advantages and disadvantages are offered by using $($a$)$ LIFO and $($b$)$ FIFO? Assume the continuing trend of increasing costs.

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