Perth Mining Company operates two mines for the purpose of extracting gold and silver. The Saddle Mine costs $28,000/day to operate, and it yields 50 oz of gold and 3000 oz of silver each of x day. The Horseshoe Mine costs $16,000/day to operate, and it yields 75 oz of gold and 1000 oz of silver each of y day. Company management has set a target of at least 650 oz of gold and 18,000 oz of silver. (a) How many days should each mine be operated so that the target can be met at a minimum cost? The minimum is C = at (x, y) = . (b) Suppose C = cx + 16,000y. Find the range of values that the Saddle Mine's daily operating cost, the coefficient c of x, can assume without changing the optimal solution. c (c) Find the range of values that the requirement for gold can assume. (requirement for gold) (d) Find the shadow price for the requirement for gold. (Round your answer to the nearest cent.)