12. Mr. Farmer has been in the business of selling cheddar cheese for almost three years, and thus far has been able to control the volume of the product by varying the selling price. He is seeking to maximize its net profit. It has been concluded that the relationship between price and demand per month is approximately D = 2500 - 10p, where p is the price per unit in dollars. The fixed cost is $ 1,100 per month, and the variable cost is $15 per unit. What is the optimal no. of units that should be produced and sold per month? What is the maximum profit per month? What are the breakeven sales quantities (range of profitable demand)? E. Selections in the Present Economy 13. The quarrying cost of marble and granite blocks plus delivery costs to the processing plant is Php 2,400.00 per cubic meter. The processing cost of marble into tiles if Php 200.00 per square meter and that of granite into tiles is Php 600.00 per square meter. If marble has a net yield of 40 square meter of block and sells at Php 400.00 per square meter, while granite gives a net yield of 50 square meters of tiles per cubic meter of block which sells at Php 1,000.00 per square meter, determine the more profitable material, considering all other costs to be the same. 14. Mineral water contains 2.5 kg. of magnesium per tonne. By using processing method of A, 82% of the metal can be recovered at a cost of P4 per tonne of water pump and processed. If method B is used, 68% of the available metal is recovered at a cost of only P2.80 per tonne of water pumped and processed. The two processes are substantially equal as to investment and time requirements. (Note: 1 tonne = 1 metric ton = 1000kgs) If the extracted metal can be sold for P2.50 per kg., which processing method should be used? How much profit will be achieved in Method A? How much profit will be achieved in Method B? At what selling price for the metal would the two processes be equally economical? 15. The Biofuels act of 2006 requires that all fuels sold in the Philippines should have a minimum 1% blend of biodiesel made from coconut, while the remainder composed of pure diesel. This is a first step of the Philippine government to lower the nation's dependence on imported oil sources. A pair of biofuel blends are being compared to the conventional pure diesel. Pure diesel costs P28.00 per liter. Pure coco-based biodiesel costs P62.00 per liter. A 5% blend of cocodiesel and 95% conventional diesel would then cost more than P28.00 per liter, causing resistance among vehicle owners. Victory Liner conducted bus runs using the two fuel variants along with the pure diesel fuel and the following data was collected: Fuel type Pure Diesel 5% blend biodiesel 10% blend biodiesel Kilometers ran 4774 1736 1736 Fuel consumption 2179 liters 677 liters 636 liters The buses used for the experiment were considered of identical condition, and the same driver was used for all trips to factor out driver effects on fuel consumption. Which fuel blend is the most economical in terms of fuel costs?