PrepTest 143, Section 1, Question 22

What we’re looking for

Working the answers

• A

  This moves from gasoline used per mile to gasoline used in total. A sports-car owner could drive very few miles while another owner drives thousands. That missing mileage comparison explains A's problem, but our shopping argument doesn't move from a rate to a total in that way.

• B

  This treats price and resistance to spoiling as enough to make frozen vegetables the better purchase overall. Fresh vegetables could have some other advantage, such as a preferred taste. That is a broader value judgment than the original's claim about economy. More importantly, B doesn't reproduce the category relationship that becomes clear in C.

• C
  Correct

  This makes me go back and notice the crucial wording: consumer cooperatives are usually cheaper, and food co-ops are one type of consumer cooperative. What if food co-ops are the exception?

  Perhaps cooperatives selling tires or other goods usually offer lower prices, while food co-ops don't. The broad pattern would still be true. We can't simply hand that usual property to every particular kind of cooperative. That's the mistake my initial shopping-list objection missed.

  Now map C. Bicycling is a type of private transportation, just as food co-ops are a type of consumer cooperative. Private transportation tends to cause more pollution per mile than public transportation, just as consumer cooperatives usually offer lower prices than other stores. Each argument applies the broad tendency to a particular subtype without establishing that it fits. Bicycles could be an exception to the pollution pattern, just as food co-ops could be an exception to the price pattern.

• D

  Better-tasting healthy food doesn't establish increased shopping at health food stores. People could buy that food in ordinary supermarkets, and “better than before” doesn't establish that it tastes at least as good as the alternatives. D has gaps between taste, choice, and where people shop. It doesn't assign a broad category's usual property to a subtype.

• E

  Fewer calories in a product doesn't establish the best weight-loss method. Increasing consumption could change total calorie intake, and the argument hasn't compared all the other methods. This jumps from one potentially useful feature to the best overall plan. It lacks the broad-category-to-subtype move that C matches.