30.Perfect Builders constructs houses. The standard labor rate is $20 per hour and the standard number of hours is 12,000 hours per home During the year t constructed 10 homes using 14,000 labor hours per home and a rate of $22 per hour. Calculate the Perfect Builders' labor rate variance a. $240,000 U b. $280,000 C. $280,000 U d. $240.000 F 31.A positve result that stems from the use of roturm on investment (ROI) is that t encourages managers to focus on a. the relationship among sales, expenses, and investment b. cost efficiency. operating asset efficiency d. the fficient use of resources in generating income e. all of these 32.Which of the following is a disadvantage of a foous on return on investment? a. It can encourage managers to focus on cost cutting efforts b. It can produce a narrow focus on divisional profitability at the expense of profitability for the overall firm. c. It can encourage managers to cut inventories and reduce overal d. It can encourage managers to focus on the long run at the expense of the e. It can accomplish all of these disadvantages. investment short run