Ted buys blocks of spruce for dollars each, and blocks of mahogany for dollars each. In a given month, Ted spends a total of dollars, where . The price of a block of mahogany, given that a block of spruce costs 5/9 as much as a block of mahogany, and Ted has bought 12 blocks of spruce and 15 blocks of mahogany for a total cost of $9750. Write an equation whose solution is the given quantity.