Answer
You can make exactly $30$ corn muffins.
Work Step by Step
Because the amount of corn muffins produced varies directly with the amount of flour available for use, you will need to multiply the number of corn muffins in one batch by the cups of flour available.
$12$ Corn Muffins x $2\frac{1}{2}$ Cups of Flours $=$ $30$ Corn Muffins.
