In the production mix problem, the meaning for the value of a dual variable is the marginal increase of the profit for the furniture company from one unit increase in the corresponding resource. Specifically, the dual variable is $10 for one hour increase in the carpenter's time, $10 for one hour increase in the painter's time, and $0 for one hour increase in the metal worker's time. What is the meaning of the value of a dual variable in the diet problem for making dog food from beef and grain? Specifically, specify the respective meanings of the dual variables for the requirements on vitamin1 and 2 and the total number of pounds of the dog food?