Now for the objective function, in the first process, running it for 1 hr, 2 barrels of gas 1 is produced, thus 9(2x1) will give the revenue from gas 1 (remember, gas 1 is sold for $9), similarly for gas 3, the process 3 generates 2 barrels of gas 3, thus the revenue from gas 3 is 24(2x3). Gas 2 sold is represented by g2, there is no need to represent it in terms of hours – plus it would have presented a problem in formulating the LP to show the amount of gas 2 from process 1 and process 2 were used in process 3. In addition, we have to account for the cost for oil and processing hours.