The following data are available for Sellco for the fiscal year ended on January $31,2023$:

$\backslash$table$[[$Sales$,1,600$ units$],[$Beginning inventory,$500$ units @$$4],[$Purchases$,$ in chronological order,$600$ units @$$5],[1,800$ units @ $$6]]$

Required:

a$.$ Calculate cost of goods sold and ending inventory under the cost flow assumptions, FIFO, LIFO and weighted average $($using a periodic inventory system$)$:

b$.$ Assume that net income using the weighted$-$average cost flow assumption is $$80,000.$ Calculate net income under FIFO and LIFO.