A learning rate of 92% 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?