Supernova29 wrote:
Could someone please explain this through options. I thought D was close.
Hi Supernova29
I'm glad to help.
ANALYZE THE STIMULUS:
Fact: Sixty years ago, average refrigerator durability was 15 years,
Fact: Now refrigerators operate continuously for more than 40 years on average.
Conclusion: at that time, people must have considered refrigerators to be nearing the end of their operational life at an age that we now consider will leave many more working years.
Assumption: The comparison of average durability is valid. On the other hand, there is
NO other factor that makes the estimation of average durability incorrect.Question: Which of the following, if true, undermines the argument above?
ANALYZE EACH ANSWER:A: Today, many more households own refrigerators than did households sixty years ago.
Wrong. "More refrigerators" says nothing about average durability increases or decreases. Thus, A does nothing to weaken the conclusion.
B: Most of the improvements in durability in the past sixty years have been achieved through cutting down on the number of refrigerators that break down in the first year of ownership.
Correct. B mentions that the comparison of the argument is INCORRECT because there is a factor virtually makes the average durability of refrigerators now increase than that of refrigerators in the past. Thus, B weakens the conclusion and is correct answer.
C: Many of the refrigerators that last an extremely long time today do so only because of engineering technology that was not available sixty years ago.
Wrong. TEMPTING but wrong. C does not weaken the conclusion, but rather strengthens the conclusion. Why? Because C means a refrigerator now can live longer because of improved engineering technology.
==> So if there is NO engineering technology the average durability of refrigerators now may be only 15 years or equal that of a refrigerator sixty years ago.
==> On the other hand, that the average durability 15 years in the past
without engineering technology = average durability 40 years now
with improved engineering technology is a CORRECT comparison.
D: The proportion of refrigerators that break down when they are between 35 years and 40 years old is significantly smaller today than is the proportion of refrigerators that break down after 40 years.
Wrong. D means almost refrigerators now can live for 40 years whereas those in the past can live only for 15 years. Thus, that
15 years in the past = 40 years now is a CORRECT comparison. D strengthens the conclusion. D is wrong.
E: More refrigerators sixty years ago received regular service than receive it today.
Wrong. E means the quality of refrigerators in the past is worse than in the current. Thus, if a refrigerator lived for 15 years sixty years ago, we definitely considered the refrigerator near the end of its life. Thus, E does not weaken the conclusion.
Hope it helps.