The rapid population growth within the boundaries of the

The rapid population growth within the boundaries of the Springfield Public School district was a source of an overcrowded school system where the student enrollments of 70 percent of them are above the state board of education's suggested limits.

A.where the student enrollments of 70 percent of them are
B.where they have 70 percent of student enrollments
C.where 70 percent of student enrollments are
D.which has 70 percent of student enrollments
E.in which 70 percent of them have student enrollments



We need to get into grammar to understand these issues. There are small details which can be used to point out the error but in the actual exam, you cannot rely on them. You will not have the time and will predominantly need to use your ear. Try to practice enough so that you don't need to get into the nitty gritty of grammar in the test.


1. Comma before which
Usually, 'which' introduces a non-restrictive clause (that is not essential to the meaning of the sentence). Non-restrictive clauses are surrounded by commas. Usually, while introducing a restrictive clause (one that is essential to the meaning of the sentence), we use 'that' and do not use a comma. Sometimes 'which' is also used to introduce restrictive clauses and it will not take a comma in that situation. GMAT does not test commas. So if you see which without a comma, do not ignore the option. To summarize, 'which' will usually come with a comma in GMAT questions but it could appear without one if it is introducing a restrictive clause. Anyway, ignore the commas as far as GMAT is concerned.

2. Where/which
They are not interchangeable. Often, 'where' and 'in which' are interchangeable. In this sentence, I would have preferred "in which" but of the given options, I will take 'where'.
'Where' is a relative adverb which can replace 'preposition + which' (in which or at which)

e.g. This is the city in which I live.
This is the city where I live.

When you use "which has..." which here acts as a relative pronoun. The sentence structure doesn't support this.

Look at two sentences:
Canada, where people are very kind, is very cold.
Canada, which has a small population, is very cold.

The structure of the two sentences is different.

Canada is very cold. People are very kind in Canada. - Canada is used as an adverb here. It is replaced by 'where'
Canada is very cold. Canada has a small population. - Canada is the subject here. It is replaced by 'which'

In our original sentence, the structure is: "70 percent of student enrollments are above the limit in the system".
Here the system is acting as an adverb and hence needs "in which"/"where".

"The system" is not the subject and hence cannot be replaced by "which has".

The rapid population growth within the boundaries of the Springfield Public School district was a source of an overcrowded school system where the student enrollments of 70 percent of them are above the state board of education's suggested limits.

A.where the student enrollments of 70 percent of them are
B.where they have 70 percent of student enrollments
C.where 70 percent of student enrollments are
D.which has 70 percent of student enrollments
E.in which 70 percent of them have student enrollments

The rapid population growth within the boundaries of the Springfield Public School district was a source of an overcrowded school system where the student enrollments of 70 percent of them are above the state board of education's suggested limits.

A.where the student enrollments of 70 percent of them are
B.where they have 70 percent of student enrollments
C.where 70 percent of student enrollments are
D.which has 70 percent of student enrollments
E.in which 70 percent of them have student enrollments

Thanks for your detail explanation Karishma but my point of confusion was that some experts say that GMAT always uses 'which' as a non-restrictive/Non-defining Relative Clause and hence must have a comma before it.

Is it explicitly clarified in any OG regrading the scope of use of 'which' in GMAT ?

Can you please share some OG/GMAT Prep instances where we have 'which' as a restrictive/defining Relative Clause without a comma before it ?

Karishma - Thanks again for further clarification.

So what I understand from your post and question 12 of OG 13 is that although GMAT mostly (say 90%-95% of the cases) doesn't use 'which' in restrictive usage BUT there can be a very few instances that a SC question may come up with 'which' in restrictive use. Right?

Please correct me if I'm wrong.

Hi karishma,
The use of where/which has always confused me.Personally I was never convinced that "where" should only be used for geographical locations but I forced myself to believe so after getting a couple of wrong answers in SC dealing with where/which.

Query 1:
So can we say for sure based on this question that "where" does not necessarily have to refer to geographical locations?

Query 2:
where/ in which, can be used interchangeably?

Now if you can please refer to the question below , please tell me , how am I to decide between options C and E, option C uses " where " and E uses " in which ".

if " where/in which " can be used interchangeably then ideally there are no differences between the 2 options?

consulting-companies-and-other-professional-services-groups-149197.html

If you could please share more links and insights showing the proper uses of " in which/ where/ which " then it could certainly help us more to get a better understanding regarding this issue.
We know use is not consistent among the various sources and this fact causes problems in understanding, however what we want is in reference to GMAT and GMAC.
How does GMAC want us to treat " where/which/in which "
As always thank you so much for your selfless assistance all your posts are highly appreciated.