Working with chemists at Virginia Tech and George Washington Universities, landscape contractor Kenneth Golding blended his own fertilizer, called "Golding-Grow." It consists of four chemical compounds, C-30, C-92, D-21, and E-11. The cost per pound for each compound is indicated as follows:

CHEMICAL COMPOUND COST PER POUND ($)

C-30 ..............0.12

C-92 ..............0.09

D-21 ..............0.11

E-11 ..............0.04

The specifications for Golding-Grow are as follows:

(1) E-11 must constitute at least 15% of the blend;

(2) C-92 and C-30 must together constitute at least 45% of the blend;

(3) D-21 and C-92 can together constitute no more than 30% of the blend;

(4) Golding-Grow is packaged and sold in 50-pound bags.

(a) Formulate an LP problem to determine what blend of the four chemicals will allow Golding to minimize the cost of a 50-pound bag of the fertilizer.

(b) Solve using a computer to find the best solution.