RBBmba@2014 wrote:"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days, people must have been considered old at age that we now consider the prime of life.

Which of the following, if true, undermines the argument above?

a. In the middle of the nineteenth century, the population of North America was significantly smaller than is today.

b. Most of the gains in life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life.

c. Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century.

d. the proportion of people who die in their seventies is significantly smaller today than is the proportion of people who die in their eighties.

e. More people in the middle of the nineteenth century engaged regularly in vigorous physical activity than do so today.

The argument assumes that there is only one explanation for the increase in average life expectancy:
In the 19th century, a person 40 years of age -- what is now considered the prime of life -- would be considered old.
In other words:
Few people in the 19th century lived beyond 40 years of age.

One way to weaken the conclusion is to suggest an ALTERNATE EXPLANATION for the increase in average life expectancy.

B: Most of the gains in life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life.
Implication:
In the 19th century, there were a greater number of infant deaths, suggesting an ALTERNATE EXPLANATION for the lower life expectancy in those days and WEAKENING the conclusion that few people in the 19th century lived beyond 40 years of age.

The correct answer is B.

Hi Mitch,
Could you please clarify why EXACTLY Option C is considered wrong ?

Doesn't Option C mean that people in the 19th century weren't really old at the time of their death, rather they died young/early because of lack of medical technology that saves people in present times, making the the AVERAGE "Life expectancy" higher now.

It seems to be that Option C is pretty close!

Look forward to your thoughts.

RBBmba@2014 wrote:Hi Mitch,
Could you please clarify why EXACTLY Option C is considered wrong ?

Doesn't Option C mean that people in the 19th century weren't really old at the time of their death, rather they died young/early because of lack of medical technology that saves people in present times, making the the AVERAGE "Life expectancy" higher now.

It seems to be that Option C is pretty close!

Look forward to your thoughts.

C: Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century.
Since the medical technology that allows people today to live to an advanced age was not available in the 19th century, the conclusion that few people in the 19th century lived beyond the age of 40 is possibly STRENGTHENED.
The correct answer choice must clearly WEAKEN the conclusion that few people in the 19th century lived beyond the age of 40.
Eliminate C.

GMATGuruNY wrote:

RBBmba@2014 wrote:Hi Mitch,
Could you please clarify why EXACTLY Option C is considered wrong ?

Doesn't Option C mean that people in the 19th century weren't really old at the time of their death, rather they died young/early because of lack of medical technology that saves people in present times, making the the AVERAGE "Life expectancy" higher now.

It seems to be that Option C is pretty close!

Look forward to your thoughts.

C: Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century.
Since the medical technology that allows people today to live to an advanced age was not available in the 19th century, the conclusion that few people in the 19th century lived beyond the age of 40 is possibly STRENGTHENED.
The correct answer choice must clearly WEAKEN the conclusion that few people in the 19th century lived beyond the age of 40.
Eliminate C.

Hello,

I like your explanation. But I am more confused with Option B "the last 150 years", does that necessarily mean the 19th century?

Thanks!
Kate

yxlucy321 wrote:

GMATGuruNY wrote:

RBBmba@2014 wrote:Hi Mitch,
Could you please clarify why EXACTLY Option C is considered wrong ?

Doesn't Option C mean that people in the 19th century weren't really old at the time of their death, rather they died young/early because of lack of medical technology that saves people in present times, making the the AVERAGE "Life expectancy" higher now.

It seems to be that Option C is pretty close!

Look forward to your thoughts.

C: Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century.
Since the medical technology that allows people today to live to an advanced age was not available in the 19th century, the conclusion that few people in the 19th century lived beyond the age of 40 is possibly STRENGTHENED.
The correct answer choice must clearly WEAKEN the conclusion that few people in the 19th century lived beyond the age of 40.
Eliminate C.

Hello,

I like your explanation. But I am more confused with Option B "the last 150 years", does that necessarily mean the 19th century?

Thanks!
Kate

The 21st century refers to the years 2001-2100.
The 20th century refers to the years 1901-2000.
The 19th century refers to the years 1801-1900.
Thus:
150 years ago = 2017 - (150 years) = 1867.
By extension:
the last 150 years = since 1867 = since the middle of the 19th century.