Only a tiny fraction of people have the radar detectors. However, one-third of tickets go to people with radar detectors.

Radar detectors are associated with increased incidence of tickets.

But how do we know that those getting caught are speeding regularly?

You don't, unless you assume it (B).

Very tricky because of all the verbiage.

B must be the answer. The argument cites high incidence of radar-equipped cars BEING TICKETED but derives a conclusion about how often these cars EXCEEDED THE SPEED LIMIT. Clearly, in the author's opinion those drivers who are often ticketed often exceed the speed limit. Thus, B is the missing link

I think the answer is D.

Assuming there are 1000 drivers on Maryland highways. 3% or 30 cars are equipped with radar detectors.

Let's say 200 cars were ticketed for speeding. 33% or 66 cars were equipped with radar detectors. this means that some cars were ticketed more than once, else one can't have 66 cars with radar detectors with originally 30 cars equipped with radar detectors.

D states this assumption.

SigEpUCI, nice explanation dear
We can look at this too:
http://www.gmatclub.com/phpbb/viewtopic ... t=maryland

Dharmin
_________________

Perseverance, Hard Work and self confidence

3% of drivers on maryland highways equip their vehicles with radar detectors
31% of all vehicles ticketed for exceeding the speed limit were equip with them
Drivers who equip their vehicles with radar detectors are more likely to exceed speed lmiit regularly than driver who do not <-- conclusion

(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.
- does not hold up the conclusion

(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.
This one holds up the conclusion. We're told a large percentage of vehicles with radar detectors were ticketed for speeding. Then (B) says those who are ticketed are likely to exceed the speed limit regularly. So the conclusion that vehicles with radar detectors exceed the speed limit regularly is true.

(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.
- not important.

(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.
- does not help the conclusion

(E) Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report.
- out of scope

A recent report determined that although only three percent of drivers on Maryland highways equipped their vehicles with radar detectors, thirty-three 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.

Please, provide explanations.

OA is a few posts below.

Source – GMATPrep by Pearson VUE

A recent report determined that although only 3% of drivers on maryland highways equipped their vehicles with radar detectors, 33% 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 rdar 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 exceded teh speed limit more often than did drivers on other state highways not covered in the report.

Pls share us your answer and explanation. Thanks.

The OA is B.

Here is the official explanation.

The conclusion concerns regularly exceeding the speed limit, but the data derive from isolated occasions when drivers exceed the speed limit and are ticketed. The conclusion thus assumes that these instances provice evidence of regular behavior - that drivers ticketed for exceeding the speed limit are likely to be drivers who regularly exceed it. Choice B states this assumption and is the best answer.

Choices A, C, and D provide additional data that might be relevant to the conclusion, but if Choice B is assumed, then additional data are unnecessary for drawing the conclusion. The difference that choice E describes between Maryland and other states would simply suggest that the report's findings cannot be extrapolated to other states. Id does not help in drawing the conclusion.

What I just don't get is the bold line in the explanation. Can someone help me out here?

A recent report determined that although only three percent of drivers on Maryland highways equipped their vehicles with radar detectors, thirty-three 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.

The conclusion concerns regularly exceeding the speed limit, but the data derive from isolated occasions when drivers exceed the speed limit and are ticketed. The conclusion thus assumes that these instances provide evidence of regular behavior-that drivers ticketed for exceeding the speed limit are likely to be drivers who regularly exceed it. Choice B states this assumption and is the best answer. Choices A, C, and D provide additional data that might be relevant to the conclusion, but if choice B is assumed, the additional data are unnecessary for drawing the conclusion. The difference that choice E describes between Maryland and other states would simply suggest that the report’s findings cannot be extrapolated to other states. It does not help in drawing the conclusion.