Ted buys [tex]w[/tex] blocks of spruce for [tex]y[/tex] dollars each, and [tex]x[/tex] blocks of mahogany for [tex]z[/tex] dollars each. In a given month, Ted spends a total of [tex]C[/tex] dollars, where [tex]C=wy+xz[/tex]. 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.