7.32 In a large lot of manufactured items, 10% contain exactly one defect and 5% contain more than one defect. If 10 items are randomly selected from this lot for sale, the repair costs total (Y1  3Y2), where Y1 denotes the number among the 10 having one defect and Y2 denotes the number with two or more defects. Find the expected value and variance of the repair costs.
Find the variance of the repair costs.