Kenneth and Patricia Golding spent a career as a husband-and wife real estate investment partnership in Calgary. When they finally retired to a 25-acre farm on northern Vancouver Island, they became ardent amateur gardeners. Kenneth planted shrubs and fruit trees, and Patricia spent her hours potting all sizes of plants. When the volume of shrubs and plants reached the point that the Goldings began to think of their hobby seriously, they built a greenhouse adjacent to their home and installed heating and watering systems.
By 2009, the Goldings realized their retirement from real estate had really only led to a second career—in the plant and shrub business—and they filed for a business licence. Within a matter of months, they asked their lawyer to file incorporation documents and formed the firm Golding Landscaping and Plants Inc.
Early in the new business’s existence, Kenneth Golding recognized the need for a high-quality commercial fertilizer that he could blend himself, both for sale and for his own nursery. His goal was to keep his costs to a minimum while producing a top-notch product that was especially suited to the Vancouver Island climate.
Working with chemists at the University of Guelph, Golding blended “Golding-Grow.” It consists of four chemical compounds, C-30, C-92, D-21, and E-11. The cost per kilogram for each compound is indicated in the following table:

Chemical                     Cost per
Compound                  Kilogram
C-30...............................    $0.24
C-92...............................      0.18
D-21...............................     0.22
E-11...............................      0.08

The specifications for Golding-Grow are established as follows:
a) Chemical E-11 must constitute at least 15% of the blend.
b) C-92 and C-30 must together constitute at least 45% of the blend.
c) D-21 and C-92 can together constitute no more than 30% of the blend.
d) Golding-Grow is packaged and sold in 25-kg bags.

Discussion Questions
1. Formulate an LP problem to determine what blend of the four chemicals will allow Golding to minimize the cost of a 25-kg bag of the fertilizer.
2. Solve to find the best solution.