Perth mining company operates two mines for the purpose of extracting gold and silver. the saddle mine costs $16,000/day to operate, and it yields 45 oz of gold and 2000 oz of silver each of x days. the horseshoe mine costs $17,000/day to operate, and it yields 70 oz of gold and 1250 oz of silver each of y days. company management has set a target of at least 750 oz of gold and 16,000 oz of silver. how many days should each mine be operated so that the target can be met at a minimum cost c in dollars