A learning rate of 92 percent on cumulative averages is realized when constructing metal storage tanks. The first tank took 1,200 hours to construct. After six tanks were constructed, the work was stopped for 2 days, after which the work resumed. Find the time required to complete units 7 through 10. If wages are $15 per hour, what was the cost of the delay from lost productivity? What was the total cost of constructing 15 tanks?