Critical Reasoning

A recent report determined that although only 3 percent of drivers on Maryland highways equipped their vehicles
with radar detectors, 33 percent of all vehicles ticketed for exceeding the speed limit were equipped with them.
Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly
than are drivers who do not.
The conclusion drawn above depends on which of the following assumptions?
(A) Drivers who equip their vehicles with radar detectors are less likely to be ticketed for exceeding the speed
limit than are drivers who do not.
(B) Drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly
than are drivers who are not ticketed.
(C) The number of vehicles that were ticketed for exceeding the speed limit was greater than the number of
vehicles that were equipped with radar detectors.
(D) Many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the
time period covered by the report.
(E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state
highways not covered in the report.


I chose D .OA is B Please explain

A recent report determined that although only 3 percent of drivers on Maryland highways equipped their vehicles
with radar detectors, 33 percent of all vehicles ticketed for exceeding the speed limit were equipped with them.
Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly
than are drivers who do not.
The conclusion drawn above depends on which of the following assumptions?
(A) Drivers who equip their vehicles with radar detectors are less likely to be ticketed for exceeding the speed
limit than are drivers who do not.
(B) Drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly
than are drivers who are not ticketed.
(C) The number of vehicles that were ticketed for exceeding the speed limit was greater than the number of
vehicles that were equipped with radar detectors.
(D) Many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the
time period covered by the report.
(E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state
highways not covered in the report.


I chose D .OA is B Please explain

Conclusion: Drivers with radar detectors are more likely to exceed the speed limit
Premise: Statistics indicate that drivers with radar detectors are more likely to receive a speeding ticket

Notice the gap here: the conclusion is about speeding, whereas the premise is about the likelihood of receiving a ticket. The premise only leads to the conclusion if it's true that cars that receive speeding tickets are, in fact, more likely to be speeding. (As opposed to, say, simply being more prone to not paying attention when police officers are stationed in the highway median.)

B tells us that those ticketed are more likely to have been speeding, so this looks good. If drivers with radar detectors are more likely to be ticketed, and those who are ticketed are more likely to have been speeding, it stands to reason that drivers with radar detectors are more likely to have sped.

D Simply tells us that of those who were ticketed, many were ticketed more than once. But this provides no information about whether those who were ticketed were more likely to have been speeding than those who weren't ticketed. They may have been unlucky or not paying attention to speed traps, etc. Moreover, 2/3 of the drivers who received tickets did not have a radar detector. It's possible that these were drivers who were receiving multiple tickets. We don't know.

Answer is B. I remember this question in Manhattan guide for CR.