Production/Storage Linear Programming Question - Solver Excel

Feb 2011

I've cracked my head over this question but still can't get it, help would be GREATLY appreciated!

B Company is involved in the wheat business. B buys and sells wheat in bulk. B uses a warehouse for storage which charges $10/average ton of wheat stored per month (based on average of beginning and ending inventory each month). The warehouse capacity is 400tons at the end of each month. B estimates what he believes the price per ton of wheat will be during each of the next 6 months as summarized below.

Month 1 - $135
Month 2 - $110
Month 3 - $150
Month 4 - $175
Month 5 - $130
Month 6 - $145

Assume that B currently has 70 tones of wheat stored in the warehouse. How many tons of wheat should B buy and sell during each of the next 6 months to maximize his profit trading wheat.
Formulate an LP model that would maximize B's profit

Thank you!

Btw, any tips on how to better understand linear programming? I'm so lost at the formulation...