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.