Critical Reasoning

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.

Why is A) not a weakener? If the # of bank robberies in La Rin is > that in Inverness, the security is obviously out of question.

OA is B

voodoo_child 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.

Why is A) not a weakener? If the # of bank robberies in La Rin is > that in Inverness, the security is obviously out of question.

A: Last year the number of bank robberies in La Rinconada was almost one-half greater than the corresponding figure for the previous year.
Several reasons to eliminate this answer choice:
1. The ratio from one year to the next tells us nothing about the actual number. It could be that the previous year there 3 bank robberies and that last year there were 4. With so few robberies, La Rinconada would have no need for extra security, STRENGTHENING the conclusion that the double doors in Inverness are a security measure.
2. An increase in the number of bank robberies in La Rinconada tells us nothing about the level of crime in INVERNESS.
3. The assumption here is that the double doors in Inverness are linked to a greater number of robbery ATTEMPTS, not a greater number of actual ROBBERIES. Thus, the number of actual ROBBERIES is beyond the scope.

The correct answer must break the link between the DOUBLE DOORS in Inverness and a greater number of ROBBERY ATTEMPTS.
B: Inverness is known for its harsh winters, while the climate of La Rinconada is quite temperate year-round.
This answer choice gives an ALTERNATE REASON for the double doors: since one of the two doors is closed at all times, the double doors in Inverness offer protection from the HARSH WINTERS, weakening the link between the double doors and more ROBBERY ATTEMPTS.

The correct answer is B.

Mitch,
Thanks for your reply. I am not sure why, in #3, you are saying that the number of actual robberies are out of scope. The whole point in this argument is to consider the security of the two individual cities. In my opinion, the conclusion is based on the number of robbery attempts. However, the assumption is not. The assumption is that the only reason why La R banks have a single set of door because the city experiences less robberies/robbery attempts.

I agree with your analysis of "ratios" in #1. However, I am not sure about #2 either. This is a weakener question. The fact that there are a greater number of robberies makes me believe that the level of crime is high. Not sufficient but it could be a necessary thought. Correct?

Thoughts?

Can you please explain what is the assumption here and how to weaken the assumption

GMATGuruNY wrote:

voodoo_child 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.

Why is A) not a weakener? If the # of bank robberies in La Rin is > that in Inverness, the security is obviously out of question.

A: Last year the number of bank robberies in La Rinconada was almost one-half greater than the corresponding figure for the previous year.
Several reasons to eliminate this answer choice:
1. The ratio from one year to the next tells us nothing about the actual number. It could be that the previous year there 3 bank robberies and that last year there were 4. With so few robberies, La Rinconada would have no need for extra security, STRENGTHENING the conclusion that the double doors in Inverness are a security measure.
2. An increase in the number of bank robberies in La Rinconada tells us nothing about the level of crime in INVERNESS.
3. The assumption here is that the double doors in Inverness are linked to a greater number of robbery ATTEMPTS, not a greater number of actual ROBBERIES. Thus, the number of actual ROBBERIES is beyond the scope.

The correct answer must break the link between the DOUBLE DOORS in Inverness and a greater number of ROBBERY ATTEMPTS.
B: Inverness is known for its harsh winters, while the climate of La Rinconada is quite temperate year-round.
This answer choice gives an ALTERNATE REASON for the double doors: since one of the two doors is closed at all times, the double doors in Inverness offer protection from the HARSH WINTERS, weakening the link between the double doors and more ROBBERY ATTEMPTS.

The correct answer is B.

Isn't it the case in this question that the author assumes the person who answers the question to know how winter season and two set of doors are linked?

Moreover, what's wrong with C? I thought C gives an alternate reason to have doors with double set of locks.

Please help me understand what am I missing.

Mitch

I too Selected C here. Can you please explain why C is wrong here?

bubbliiiiiiii wrote:Isn't it the case in this question that the author assumes the person who answers the question to know how winter season and two set of doors are linked?

Moreover, what's wrong with C? I thought C gives an alternate reason to have doors with double set of locks.

Please help me understand what am I missing.

shekhar.kataria wrote:Mitch

I too Selected C here. Can you please explain why C is wrong here?

bubbliiiiiiii wrote:Isn't it the case in this question that the author assumes the person who answers the question to know how winter season and two set of doors are linked?

Moreover, what's wrong with C? I thought C gives an alternate reason to have doors with double set of locks.

Please help me understand what am I missing.

C: The mechanism of the double doors used by banks in Inverness allows bank SECURITY personnel to lock the doors remotely.
This answer choice links the double doors to SECURITY personnel, STRENGTHENING the contention that the double doors are a SECURITY MEASURE. The correct answer must provide an ALTERNATE reason for the doors that is NOT associated with security.

"It's cold! Close the door!"
One purpose of a door is to KEEP OUT THE COLD.
B states that Inverness is known for HARSH WINTERS.
The double doors are operated by a mechanism that allows only one set of doors to be open at a time, with the result that one set will be CLOSED at all times.
No special knowledge -- just a bit of common sense -- is needed to conclude that the harsh winters provide an ALTERNATE REASON for the double doors: TO KEEP OUT THE COLD.

According to GMAT we have to choose the best possible answers from the given set of options and here B is the best comparing to other choices.

I have a question to the expert here that the Option C (in the below question)can be visualize from the point that LOCKING OF THE DOUBLE DOOR REMOTELY OFFERS EASINESS TO THE SECURITY PERSONNEL (an alternate reason). So it weakens the argument.

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?

c) The mechanism of the double doors used by banks in Inverness allows bank security personnel to lock the doors remotely.

Thanks for the quick and crisp response RON, I got what you are trying to elucidate here. I will try to reframe my way of thinking now on wards.