Let $c$ be the number of pounds of corn and $b$ be the number of pounds of beans.
From the given information, we have the system of equations:
\begin{align*}
c + b &= 24 \\
0.99c + 0.45b &= 18.09
\end{align*}
We can solve this system of equations by substitution or elimination. Let's use elimination:
Multiply the first equation by $0.45$ to get $0.45c + 0.45b = 10.8$.
Subtracting this equation from the second equation, we get $0.54c = 7.29$.
Dividing both sides by $0.54$, we find $c \approx 13.5$.
So, Shea bought approximately $\boxed{13.5}$ pounds of corn.
The answer is: 13.5
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Shea purchases a total of 24 pounds of corn and beans, with corn costing 99 cents per pound and beans costing 45 cents per pound. The total cost of the purchase is $18.09. How many pounds of corn did Shea buy, rounded to the nearest tenth?

### Answer:
