voodoochild wrote:
Each bank in the town of La Rinconada has only a single set of locking doors at its entrance. In the town of Inverness, on the other hand, the entrances to nearly all banks are equipped with two sets of locking doors, operated by a mechanism that allows only one set of doors to be open at a time. It is clear, then, that banks in Inverness experience more robbery attempts than do those in La Rinconada, and have thus adopted the extra doors as a security measure.
Which of the following, if true, most weakens the argument above?
(A) Last year the number of bank robberies in La Rinconada was almost one-half greater than the corresponding figure for the previous year.
(B) Inverness is known for its harsh winters, while the climate of La Rinconada is quite temperate year-round.
(C) The mechanism of the double doors used by banks in Inverness allows bank security personnel to lock the doors remotely.
(D) Bank robbery attempts are typically unsuccessful, and, even when the robbers do manage to escape with stolen money, the sum is usually quite small.
(E) Inverness has almost twice as many police officers per capita as does La Rinconada.
OFFICIAL EXPLANATION
(1) Identify the Question Type
The question asks us to weaken the argument presented, so this is a
Weaken the Conclusion question.
(2) Deconstruct the Argument
The argument attempts to explain why almost all banks in Inverness have separately locking double doors, in contrast to the total lack of such doors in the town of La Rinconada. The argument concludes that the double doors must be an extra security measure against crime, and that, by extension, the rate of the relevant crime (here, bank robbery) must be higher in Inverness than in La Rinconada.
(3) State the Goal
For Weaken questions, we have to find an answer that makes the conclusion at least a little less likely to be true or valid.
The explanation presented in the argument does seem reasonable - certainly, one reason for using double doors could be security concerns. The argument can be attacked, though, on the grounds that it claims this must be the reason. If there are other possible reasons for using the double doors, then the claim that the doors are used due to security concerns and a higher robbery rate becomes less likely to be true.
(4) Work from Wrong to Right
(A) The year-over-year growth rate of bank robberies in La Rinconada alone is not helpful in making a comparison between La Rinconada and another town.
(B) CORRECT. The door mechanism in Inverness creates an effective barrier against harsh winter winds and cold air: At no point will both sets of doors be open at the same time, so the introduction of cold air into the bank will be minimized relative to a typical single door opening. This choice thus provides an alternative rationale for the presence of the double doors, weakening the force of the original conclusion.
(C) This choice actually strengthens the argument: If the double doors are equipped with such a feature, it becomes more reasonable to speculate that they were installed as a safeguard against crime. Also, this choice can be eliminated immediately on the grounds that it doesn't distinguish at all between the two towns, and thus provides no reason for the door system to be present in Inverness but not also in La Rinconada.
(D) This choice does not address the argument's conclusion: the reason for the presence of double doors in Inverness banks and the lack of double doors in La Rinconada banks.
(E) The proportion of citizens who are police officers does not provide meaningful information about bank-robbery rates in the two towns, or about the reason for the presence of double doors in Inverness banks and the lack of double doors in La Rinconada banks.