gmat逻辑削弱题例题
1. Homeowners aged 40 to 50 are more likely to purchase ice cream and are more likely to purchase it in larger amounts than are members of any other demographic group. The popular belief that teenagers eat more ice cream than adults must, therefore, be false.
The argument is flawed primarily because the author
A. Fails to distinguish between purchasing and consuming
B. Does not supply information about homeowners in age groups other than 40 to 50
C. Depends on popular belief rather than on documented research findings
D. Does not specify the precise amount of ice cream purchased by any demographic group
E. Discusses ice cream rather than more nutritious and healthful foods
2. Opponents of laws that require automobile drivers and passengers to wear seat belts argue that in a free society people have the right to take risks as long as the people do not harm other as a result of taking the risks. As a result, they conclude that it should be each person’s decision whether or not to wear a seat belt.
Which of the following, if true, most seriously weakens the conclusion drawn above?
A. Many new cars are built with seat belts that automatically fasten when someone sits in the front seat.
B. Automobile insurance rates for all automobile owners are higher because of the need to pay for the increased injuries or deaths of people not wearing seat belts.
C. Passengers in airplanes are required to wear seat belts during takeoffs and landings.
D. The rate of automobile fatalities in states that do not have mandatory seat belt laws is greater than the rate of fatalities in states that do have such laws.
E. In automobile accidents, a greater number of passengers who do not wear seat belts are injured than are passengers who do wear seat belts.
3. Offshore oil-drilling operations entail an unavoidable risk of an oil spill, but importing oil on tankers presently entails an even greater such risk per barrel of oil. Therefore, if we are to reduce the risk of an oil spill without curtailing our use of oil, we must invest more in offshore operations and import less oil on tankers.
Which of the following, if true, most seriously weakens the argument above?
A. Tankers can easily be redesigned so that their use entails less risk of an oil spill.
B. Oil spills caused by tankers have generally been more serious than those caused by offshore operations.
C. The impact of offshore operations on the environment can be controlled by careful management.
D. Offshore operations usually damage the ocean floor, but tankers rarely cause such damage.
E. Importing oil on tankers is currently less expensive than drilling for it offshore.
4. The average normal infant born in the United States weighs between 12 and 14 pounds at the age of three months. Therefore, if a three-month-old child weighs only 10 pounds, its weight gain has been below the United States average.
Which of the following indicates a flaw in the reasoning above?
A. Weight is only one measure of normal infant development.
B. Some three-month-old children weigh as much as 17 pounds.
C. It is possible for a normal child to weigh 10 pounds at birth.
D. The phrase "below average" does not necessarily mean insufficient.
E. Average weight gain is not the same as average weight.
5. (Z4-20)Five years ago, as part of a plan to encourage citizens of Levaska to increase the amount of money they put into savings, Levaska’s government introduced special savings accounts in which up to $3,000 a year can be saved with no tax due on the interest unless money is withdrawn before the account holder reaches the age of sixty-five. Millions of dollars have accumulated in the special accounts, so the government’s plan is obviously working.
Which of the following, if true, most seriously weakens the argument?
A. A substantial number of Levaskans have withdrawn at least some of the money they had invested in the special accounts.
B. Workers in Levaska who already save money in long-term tax-free accounts that are offered through their workplace cannot take advantage of the special savings accounts introduced by the government.
C. The rate at which interest earned on money deposited in regular savings accounts is taxed depends on the income bracket of the account holder.
D. Many Levaskans who already had long-term savings have steadily been transferring those savings into the special accounts.
E. Many of the economists who now claim that the government’s plan has been successful criticized it when it was introduced.
