methevoid wrote:
A career in dermatology is still a safe bet for medical school graduates. In the U.S., the number of cases of skin cancer linked to ultraviolet (UV) radiation in sunlight has remained relatively constant every year even though far fewer adults are intentionally exposing themselves to UV sunlight now than were doing so at the height of the suntan craze 20 years ago.
Each of the following, if true, could explain the relative stability in the incidence of skin cancer each year despite the decrease in intentional exposure to UV sunlight EXCEPT:
(A) Because of decreasing levels of ozone in the upper atmosphere, more people are now exposed accidentally to excessive UV sunlight.
(B) People who continue to intentionally expose themselves to UV sunlight are absorbing larger doses of the harmful radiation than the average sun-tanner did in the past.
(C) Levels of UV radiation from sources other than sunlight are increasing every year.
(D) While fewer women are intentionally exposing themselves to UV sunlight, the number of men doing so has increased significantly.
(E) In most victims, skin cancer is linked to exposures to UV sunlight that occurred up to 30 years before the onset of the disease.
Can someone explain why B is wrong?
My logic is,
Say
earlier there were
Total number of people = 100 ( 60 intentionally exposing +40 other reasons ).
Now
Total number of people =100 ( 20 intentionally exposing +80 other reasons )
So ,now these 20 people can expose as much they can, but they cannot effect the total number.
Atleast they can not increase the total number.
So, Why B is wrong, when it is giving us information about intensity of exposure.
And cancer rate is no where in ques. Argument is only about total number of cases.
KAPLAN OFFICIAL EXPLANATION
Here's another question that touches on a whole bunch of the logical elements we've been discussing. We're asked to find the choice that could not possibly explain a phenomenon. This tells us that four of the answer choices could possibly explain the paradoxical phenomenon. As always, read the stimulus carefully, paying close attention to the details and what they imply. Here's the story: Since far fewer adults are intentionally exposing themselves to UV sunlight today compared to 20 years ago, the number of cases of skin cancer linked to exposure to the UV radiation in sunlight should be decreasing. But the passage creates a seeming paradox, because the number of cases of skin cancer has actually remained constant every year. Four of the answer choices will resolve the paradox by providing alternative explanations for the phenomenon of skin cancer that are not related to the total number of adults today who are intentionally exposing themselves to sunlight. The correct answer will leave the paradox intact.
An 800 test taker has a sense for what the right and wrong choices will look like or do, even when, in an "odd-man-out" situation, she can't pre-phrase such choices precisely.
(D) is the one that does not help to resolve the paradox. Even if the number of men who are intentionally exposing themselves to UV sunlight has increased, we still know from the stimulus that far fewer adults altogether are intentionally exposing themselves. So the mystery remains: the rate of skin cancer among adults altogether should be decreasing, although we're told it's not.
(D) is the answer. The other four choices, however, do provide acceptable solutions to the mystery:
(A) Accidental exposure to UV sunlight may be compensating for the decrease in intentional exposure, keeping the cancer rate the same.
(B) The cancer rate among people who intentionally expose themselves to UV sunlight may be higher because they are getting a larger dose of the harmful rays, thus keeping the overall cancer rate the same.
(C) If levels of UV radiation from sources other than sunlight are increasing, that could compensate for the decrease in intentional exposure to the sun.
(E) If skin cancer is linked to exposures to sunlight that occurred up to 30 years before the onset of the disease, then the decrease in intentional exposure to UV sunlight in recent years probably does not yet show up in the rate of skin cancer.