Mrs. simpson buys loaves of bread and quarts of milk each week at prices of $1 and 80 cents, respectively. at present she is buying these products in amounts such that the marginal utilities from the last units purchased of the two products are 80 and 70 utils, respectively.

Mrs. Simpson should buy less bread and more milk.

Explanation:

Besides the nutritional differences between bread and milk, Mrs. Simpson is not buying the utility-maximizing combination of bread and milk.

When she purchases bread, she is paying $1 for 80 utils, that means that the marginal cost of every util is 1.25¢.

When she purchases milk, she is paying $0.80 for 70 utils, that means that the marginal cost of every util is 1.14¢.

So the marginal cost per additional util is lower for milk.