Question

In an effort to save energy and, thus, money, many people keep their electric freezers halfempty at all times, using them to store prefrozen foods bought at a store and nothing else. Yet freezers that are half-empty usually consume more energy than they would if they were kept fully stocked. Which of the following, if true, contributes most to an explanation for the apparent discrepancy described above? A person who normally maintains a halfempty freezer would save a considerable amount of money by using a freezer that is half as large. An electric freezer can operate efficiently only if chilled air is free to circulate within the freezing compartment. A given volume of air in a freezer requires much more energy to be maintained at a temperature below freezing than does an identical volume of frozen food. The door of a full freezer is likely to be opened more often, and for a longer period of time, than is the door of a halfempty freezer. On average, it takes less energy to keep food frozen than it does to get it from room temperature to a frozen state.

Short answer

Statement C: A given volume of air in a freezer requires much more energy to be maintained at a temperature below freezing than does an identical volume of frozen food.

Step-by-step solution

Analyze each statement

We have to evaluate each of the given options whether they logically explain the discrepancy mentioned above.

Evaluate statement A

The statement suggests that saving occurs with a smaller freezer, but does not address why less content in the freezer results in more energy consumption. Hence, rejected.

Evaluate statement B

While circulation of chilled air is important, the statement fails to explain why more energy is used when freezer is half-empty. So, this explanation is not sufficient.

Evaluate statement C

This statement proposes that maintaining a given volume of air in a freezer at a temperature below freezing requires more energy than maintaining an identical volume of frozen food. This rationale justifies why a half-empty freezer (more air) would consume more energy and hence, explains the apparent discrepancy.

Evaluate statement D

This statement suggests that a full freezer is opened more often, which would likely lead to more energy consumption, yet it does not explain why a half-empty freezer uses more energy. Hence, rejected.

Evaluate statement E

While this provides a useful piece of information, it does not explain why a half-empty freezer consumes more energy. Hence, rejected.

Key concepts

GMAT energy consumption question

When studying for the GMAT, you may come across complex problem-solving questions that require you to analyze and explain discrepancies. A common topic is energy consumption, which intersects with everyday situations, providing relatable scenarios.

For instance, consider the question about whether a half-empty freezer consumes more energy than a fully stocked one. The correct answer hinges on understanding the principles of thermal energy and insulation. A fully stocked freezer keeps the cold better because the frozen items act as insulators. Each item retains the cold, reducing the amount of energy needed to maintain low temperatures. On the other hand, a half-empty freezer has more air space, and since air doesn't hold the cold as well as solid frozen items, the freezer must work harder, thus using more energy.

Being aware of scientific principles such as these can significantly help in tackling GMAT energy consumption questions. They often expect you to apply basic scientific knowledge to explain a situation or solve a problem.

Test Preparation Strategies

Preparing for the GMAT requires a strategic approach, combining time management, practice, and analysis of both your strong and weak areas. Start with a diagnostic test to establish a baseline of your current abilities. Following this, create a study plan that focuses on improving weaker areas while maintaining strengths.

To bolster your preparation for problem-solving questions like the energy consumption discrepancy:

• Practice regularly with a wide variety of sample questions to familiarize yourself with the test format and question types.
• Time your practice sessions to increase your speed and accuracy under exam conditions.
• Review the explanations rigorously for every question, especially the ones you get wrong, in order to learn from your mistakes.
• Focus on learning the underlying concepts rather than just memorizing solutions.

Ensure you also get adequate rest and maintain a balanced lifestyle, as these factors can significantly impact your concentration and performance during your test preparation.

Critical Reasoning in GMAT

Critical reasoning is a vital part of the GMAT, assessing your ability to analyze arguments, identify assumptions, and evaluate the evidence provided. In the context of a GMAT energy consumption question, the test-taker must discern which statement, among several plausible options, best explains a given discrepancy.

Using the example provided, the critical reasoning approach involves analyzing each statement and its implications:

• Evaluate the logic behind each answer choice.
• Identify irrelevant information that might be misleading.
• Look for the answer that directly addresses the discrepancy in question.

Remember that the GMAT tests your reasoning skills rather than purely your knowledge base. Developing these skills requires practice with an emphasis on understanding argument structures and correctly interpreting information. As you prepare, focus on breaking down arguments methodically and objectively assessing the evidence presented.