This question contains two parts a) and b). Answer both parts: Mary and her husband Andrew are planning their dream house. The house will sit high on a hill with a spectacular view of the Blue Mountains. The architectural plans show the size of the house to be 3,000 square feet. The average price for a lot and house similar to this one is $160 per square foot. Luckily, Andrew is a retired plumber and believes he can save money by installing the plumbing himself. Mary also feels she can take care of the interior decorating. The following average cost information is available from a local bank that makes loans to local contractors and also releases progress payments to contractors when specific tasks are completed: 24% Excavation and framing complete 8% Roof and fireplace complete 3% Wiring roughed in 6% Plumbing 5% Siding on 17% Windows, insulation, walks, plaster, and garage complete 9% Furnace installed 4% Plumbing fixtures installed 10% Exterior paint, light fixtures installed, finish hardware installed 6% Carpet and trim installed 4% Interior decorating 4% Floors laid and finished a) What is the estimated cost for the house if Mary and Andrew use contractors to complete all of the house? - show as much working (calculations) as you can to support your answer: 10 marks b) Estimate what the cost of the house would be if the Mary and Andrew use their talents to do some of the work themselves (t.e. the Plumbing and Interior decorating) - show as much working (calculations) as you can to support your answer: 10 marks