四、Winans Company uses the lower-of-cost-ov-Net realizable value method, on an individual-item basis, in pricing its inventory items. The inventory at December 31 ,2007, included product X, Relevant per-unit data for product X appear below. 
rhere were 4,000 units of product X on hand at December 31,2007, Product X was incorrectly valued al $40 per unil for reporting purposes.Instructions: (20 分）
(a)Compute the effect of ill is error on net income for 2007 and the effect on net income for 2008.