JPM is just about to launch a new product. Production capacity means that a maximum of 120 units can be manufactured each week and manufacture must be in batches of ten. The marketing department estimates that at a price of $120 no units will be sold but, for each $3 reduction in prices, ten additional units per week will be sold. Fixed costs associated with manufacturing the product are expected to be $6,000 per week. Variable costs are expected to be $40 per unit for the first eight batches, but after that the unit variable cost of the products in the batch will be $2 more than those in the preceding batch. Which is the most profitable level of output per week