Solve the Standard Minimization Problem Using Duality $C = 18 s + 21 t$

Short Answer

Solve the standard minimization problem using duality. Minimize $C = 18 s + 21 t$ subject to the following.
​ $$\begin{array} { l } 3 s + 2 t \geq 48 \\7 s + 3 t \geq 56 \\s \geq 0 , t \geq 0\end{array}$$ ​ $$C =$$ __________
​ $$s =$$ __________
​ $$t =$$ __________