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33. a) A new cottage is built across the river and 300 m warb verge downstream from the nearest telephone relay station. The river is 120 m wide. In order to wire the cottage for phone service, wire will be laid across the river under water, and along the edge of the river above ground. The cost to lay wire under water is $15 per m and the cost to lay wire above ground is $10 per m. How much wire should be laid under water to minimize the cost? Be sure to check that your answer is indeed a minimum. (11 marks) b) Currently 2000 people attend performances of The Sound of Music if tickets cost $40. Expenses are $8 per person in attendance for each performance. For each $2 decrease in the ticket price, 200 more people attend. Calculate the ticket price that produces maximum profit. (7 marks)