Chapter 5.5, Problem 12E

In Exercises 9-22, solve the given standard minimization problem using duality: (You may already have seen some of these in earlier sections, but now you will be solving them using a different method.] [HINT: See Example 1]

Minimize $c=3s+2t$ subject to $s+2t\ge 20$

$2s+t\ge 10$

$s\ge 0,t\ge 0$.