At least 100 students at a certain high school study ....

[alexei600]

Hi,
I still do not get why whould the question give us the value of at least 100 studebts, whereas we donot really employ this value. As been shown above, we just assign a variable.
Thanks.

[jnelson0612]

Alexei, please go back and read Ron's first post, particularly the part in which he talks about statement 1. That will help you understand the relevance of that particular piece of information.

[behram14]

Hi sorry to dig up an old topic but can someone please clarify one point for me: when it's mentioned that 4 percent of the students who study french also study Japanese does this mean the the number of students who study both (let's say B) is: B = 0.04F or does it mean that B = 0.04F + x*J ?

From the solution it appears that it's the former, and that's the basis for being able to solve the question, because B = 0.04F = 0.1J, therefore F>J.

[RonPurewal]

Hi sorry to dig up an old topic but can someone please clarify one point for me: when it's mentioned that 4 percent of the students who study french also study Japanese does this mean the the number of students who study both (let's say B) is: B = 0.04F or does it mean that B = 0.04F + x*J ?

it's the former, because all of these people are also in the "study french" group.
if you were to write the latter, you would be double-counting all of them.

[jeffrey.k.l.ho]

I'm really trying to understand why my method is wrong, can someone please shed some light?
F= students studying french
0.04F = Number of French Students studying japanese.

For Statement 2:
0.04F = 0.01 x GT 100
I substituted the number of students studying japanese with GT 100 as given in the question.

I get F = GT25

Therefore the number of students studying French = GT 25 which can be more or less than the number of people Studying japanese (GT 100). Therefore E.

Is my reasoning wrong?

[RonPurewal]

what is "GT"? i'm not familiar with that notation.

[jeffrey.k.l.ho]

My apologies. GT = Greater than.

[jeffrey.k.l.ho]

According to my logic described in my previous post, Statement 2 should be insufficient. Is there something wrong with this logic?

[RonPurewal]

According to my logic described in my previous post, Statement 2 should be insufficient. Is there something wrong with this logic?

yes. you're ignoring the fact that these quantities are actually proportional to each other -- in other words, you're assuming that the two quantities can vary independently of each other.

here's your logic applied to another case:
I'm twice as tall as my little cousin.
I am over 6 feet tall ("GT 6" in the notation you were using)
Therefore, he is over 3 feet tall ("GT 3" in that notation)
... so far so good. but, you have to make sure you realize that my cousin still has to be half my height. your mistake, if extended to this case, would be to think that my height can be any height over 6 feet *and* that my cousin's height can simultaneously be any height over 3 feet, and that you thus don't know who's taller.

[nipunjindal91]

Hi sorry to dig up an old topic but can someone please clarify one point for me: when it's mentioned that 4 percent of the students who study french also study Japanese does this mean the the number of students who study both (let's say B) is: B = 0.04F or does it mean that B = 0.04F + x*J ?

it's the former, because all of these people are also in the "study french" group.
if you were to write the latter, you would be double-counting all of them.

Hi Ron,

I faced this question in the GMAT prep software, and had the same doubt which doesn't seem to be exactly clarified here.
As you said in your last post that if we take the latter, i.e. B=0.04F + x*J (where x can be = 0.1 as per statement 2 in the question), we would double counting- can you please explain the same? how would lead to double counting?

Thanks.

[RonPurewal]

Hi sorry to dig up an old topic but can someone please clarify one point for me: when it's mentioned that 4 percent of the students who study french also study Japanese does this mean the the number of students who study both (let's say B) is: B = 0.04F or does it mean that B = 0.04F + x*J ?

it's the former, because all of these people are also in the "study french" group.
if you were to write the latter, you would be double-counting all of them.

Hi Ron,

I faced this question in the GMAT prep software, and had the same doubt which doesn't seem to be exactly clarified here.
As you said in your last post that if we take the latter, i.e. B=0.04F + x*J (where x can be = 0.1 as per statement 2 in the question), we would double counting- can you please explain the same? how would lead to double counting?

Thanks.

There's not much explaining I can do beyond what's already there. If it's still confusing, try throwing specific numbers in there, and see whether it makes more sense.
Also, "study French" and "study Japanese" are annoyingly similar, making it harder to think about what's going on. So I'm going to replace them with "boy" and "redhead".

Prompt:
"4 percent of the boys at the school are redheads"
Say there are 100 boys. Then there must be 4 redheaded boys.
Statement 2:
"10 percent of the red-haired students are boys"
We already know there are 4 redheaded boys. For this statement to be true, there must be 40 redheads.

Now just try the equations and see what works. You'll see what I mean by "double count".