Step 1 :This is a linear programming problem. We are asked to minimize the objective function \(c=x+2y\) subject to the constraints \(x+4y \geq 18\), \(7x+y \geq 18\), and \(x \geq 0, y \geq 0\).
Step 2 :We can solve this problem using a method for linear programming.
Step 3 :The optimal value of the objective function is 10.0, and the values of x and y that achieve this minimum are 2.0 and 4.0, respectively.
Step 4 :Final Answer: \(c=\boxed{10}\), \((x, y)=(\boxed{2}, \boxed{4})\)