Data Sufficiency

[Khalid]

Source: GMAT Practice test [EDITED BY STACEY: THIS IS NOT A SUFFICIENT SOURCE. PLEASE LIST THE AUTHOR'S NAME. If this is not done, we will have to delete this thread!]

Are at least 10% of the people in country X who are 65 years old or older employed?

1) In country X, 11.3% of the population is 65 years old or older
2 In country X, of the population 65 years old or older, 20% of the men and 10% of the women are employed

I had picked C but the correct is B. I had thought B wasnot sufficient since I don't know what % of the population is 65 yrs oldor older. The stem says of the population and that didn't seem sufficient. Can someone please help?

thx

[shaji]

Consider the following
m=men who are >=65 and w=women who are >=65 and x be he proportion of these who r employed.
The Question is Is x>=10?

Therefore from Statement 2; x=(0.2m+0.1w)/(m+w).Not sufficient!!!

The correct answer is E

Source: GMAT Practice test

Are at least 10% of the people in country X who are 65 years old or older employed?

1) In country X, 11.3% of the population is 65 years old or older
2 In country X, of the population 65 years old or older, 20% of the men and 10% of the women are employed

I had picked C but the correct is B. I had thought B wasnot sufficient since I don't know what % of the population is 65 yrs oldor older. The stem says of the population and that didn't seem sufficient. Can someone please help?

thx

[rahul]

Even i got the answer as E

[aadi]

I got B and here is how i got to B:

Assume the pop of 65 and older is 100

A. 100 = 11.3% of the ENTIRE population - No info on employment - NOT SUFF

B. Of population 65 and older (in this case 100)
20% or 20 men 65 and older are employed AND
10% or 10 women 65 and older are employed
A total of 30 people > 65 are employed out of a possible 100. - SUFF
So B is the answer

Source: GMAT Practice test

Are at least 10% of the people in country X who are 65 years old or older employed?

1) In country X, 11.3% of the population is 65 years old or older
2 In country X, of the population 65 years old or older, 20% of the men and 10% of the women are employed

I had picked C but the correct is B. I had thought B wasnot sufficient since I don't know what % of the population is 65 yrs oldor older. The stem says of the population and that didn't seem sufficient. Can someone please help?

thx

[shaji]

Getting to B does not make B the correct answer.

Notice the flaw:

You are assuming 20% of the pop of age 65 and above are men and the same wih the women.!!!

I got B and here is how i got to B:

Assume the pop of 65 and older is 100

A. 100 = 11.3% of the ENTIRE population - No info on employment - NOT SUFF

B. Of population 65 and older (in this case 100)
20% or 20 men 65 and older are employed AND
10% or 10 women 65 and older are employed
A total of 30 people > 65 are employed out of a possible 100. - SUFF
So B is the answer

Source: GMAT Practice test

Are at least 10% of the people in country X who are 65 years old or older employed?

1) In country X, 11.3% of the population is 65 years old or older
2 In country X, of the population 65 years old or older, 20% of the men and 10% of the women are employed

I had picked C but the correct is B. I had thought B wasnot sufficient since I don't know what % of the population is 65 yrs oldor older. The stem says of the population and that didn't seem sufficient. Can someone please help?

thx

[RonPurewal]

there is no flaw; the answer is definitely b.

we can make short work of statement 1, which tells us nothing at all about what we're interested in. it tells us the proportion of the total population that is over 65, but we don't care about that - we want to know about proportions of the over-65 proportion. therefore, statement 1 is totally useless (and hence insufficient).

statement 2:
- first, note that we have no idea what proportion of the over-65 population is male and what proportion is female.
BUT
we know that at least 10% of both sexes are employed. that guarantees that at least 10% of the total population will be employed!
if you don't understand this, think about it this way:
- if the population is entirely female, then 10% will be employed. --> answer = yes
- if the population is mixed, then somewhere between 10% and 20% will be employed (depending on how heavily male / female the population is) --> answer = yes
- if the population is entirely male, then 20% will be employed. --> answer = yes
so #2 is sufficient.

do note that #2 is insufficient to determine the exact percentage of the over-65's that are employed - but go back and look at the question prompt: we don't care!

answer = b

[shaji]

The answer is definitely B as explained. A very important and interesting concept.

The flaw in 'aadi's' reasoning remains!!!

there is no flaw; the answer is definitely b.

we can make short work of statement 1, which tells us nothing at all about what we're interested in. it tells us the proportion of the total population that is over 65, but we don't care about that - we want to know about proportions of the over-65 proportion. therefore, statement 1 is totally useless (and hence insufficient).

statement 2:
- first, note that we have no idea what proportion of the over-65 population is male and what proportion is female.
BUT
we know that at least 10% of both sexes are employed. that guarantees that at least 10% of the total population will be employed!
if you don't understand this, think about it this way:
- if the population is entirely female, then 10% will be employed. --> answer = yes
- if the population is mixed, then somewhere between 10% and 20% will be employed (depending on how heavily male / female the population is) --> answer = yes
- if the population is entirely male, then 20% will be employed. --> answer = yes
so #2 is sufficient.

do note that #2 is insufficient to determine the exact percentage of the over-65's that are employed - but go back and look at the question prompt: we don't care!

answer = b

[rahul]

Thank You Ron

[Guest]

Actually it doesnt matter what the propotion of men and women are in the population. In my case since I picked 100, the population of women could be 10 or 99, you will still get the same answer that at least 10% of the pop 65 or older is employed.

For example: let there be 80 men and 20 women in my population - 20% of men = 16 and 10% of women = 2 --> at least 10% employed

even if you take 99 women and 1 man --> 10% = 9.9 women and 0.2 men still leads you to the conclusion that at last 10% is employed

Getting to B does not make B the correct answer.

Notice the flaw:

You are assuming 20% of the pop of age 65 and above are men and the same wih the women.!!!

I got B and here is how i got to B:

Assume the pop of 65 and older is 100

A. 100 = 11.3% of the ENTIRE population - No info on employment - NOT SUFF

B. Of population 65 and older (in this case 100)
20% or 20 men 65 and older are employed AND
10% or 10 women 65 and older are employed
A total of 30 people > 65 are employed out of a possible 100. - SUFF
So B is the answer

Source: GMAT Practice test

Are at least 10% of the people in country X who are 65 years old or older employed?

1) In country X, 11.3% of the population is 65 years old or older
2 In country X, of the population 65 years old or older, 20% of the men and 10% of the women are employed

I had picked C but the correct is B. I had thought B wasnot sufficient since I don't know what % of the population is 65 yrs oldor older. The stem says of the population and that didn't seem sufficient. Can someone please help?

thx

[StaceyKoprince]

Hi, guys

It is not sufficient to list "GMAT practice test" as the source. The author of the content has to be identified clearly (eg, GMATPrep practice test, MGMAT practice test, whatever).

If the author is not listed, this thread will be deleted - so, Khalid, please post the author's name. Thanks!