The average total cost curves for plants A, B, C and D are shown in the above figure. Which plant is best to use to produce 80 units per day?

Mrs. Green is spending all her money income by buying bottles of soda and bags of pretzels in such amounts that the marginal utility of the last bottle is 60 utils and the marginal utility of the last bag is 30 utils. The prices of soda and pretzels are $.60 per bottle and $.40 per bag respectively. It can be concluded that:

A) the two commodities are substitute goods. B) Mrs. Green should spend more on pretzels and less on soda. C) Mrs. Green should spend more on soda and less on pretzels. D) Mrs. Green is buying soda and pretzels in the utility-maximizing amounts.

The question below are based on the following four sets of data-pairs: (1) A and B, (2) C and D, (3) E and F, and (4) G and H. In each set, the independent variable is in the left column and the dependent variable is in the right column

Which of the four sets of data pairs shows an inverse relationship between the independent and dependent variable?

A. 1 and 3
B. 2 and 3
C. 3 and 4
D. 2 and 4