how did they get this

We receive $5.25 in revenue for every unit of Product A we produce. We receive $3 in revenue for every unit of Product B we produce. Producing one unit of Product A requires 20 pounds of material, 25 hours of machine capacity, and 20 hours of labor. Producing one unit of Product B requires 6 pounds of material, 20 hours of machine capacity, and 30 hours of tabor. We have available 600 pounds of material, 1,000 hours of machine capacity, and 1,200 hours of labor. Use linear programming to find the optimal product mix, and report the total revenue that will be received if this mix is produced. (Round to 2 decimal places)