Some primate researchers have hypothesized that the proportion of empathetically-inclined chimpanzees that yawns contagiously exceed the proportion of non-empathetically-inclined chimpanzees who do.

A.exceed the proportion of non-empathetically-inclined chimpanzees who do
B.exceed that of non-empathetically-inclined chimpanzees
C.exceeds those who are non-empathetically-inclined
D.exceeds the proportion of non-empathetically-inclined chimpanzees that does that
E.exceeds the proportion of non-empathetically-inclined chimpanzees that does so

The source is the Kaplan Hard SC Q Banks.

I don't quite get what you mean by proportion with countable noun in relation to this question. Perhaps you could elaborate a little?

Here is the official explaination:

Scanning the answer choices, we immediately see "exceed" versus "exceeds". The subject here is "proportion" which is singular, so the verb should be "exceeds". Therefore we eliminate (A) and (B). (A) has the additional problem of using "who" to refer to animals. Generally, "that" is preferred to "who" when referring to animals. This leaves us with (C), (D) and (E).

(C) contains a parallelism problem: It compares "the proportion of . . ." with "those (chimpanzees)". For the sake of parallelism, it should compare either chimpanzees with chimpanzees, or the proportion with the proportion. So we eliminate (C).

(D) contains the unidiomatic "that does that", so (D) is incorrect. The GMAT prefers "does so" (or "do so") to "does that" (or "do that").

(E) correctly tackles four issues: (i) It uses the singular verb form "exceeds"; (ii) it compares "the proportion" with "the proportion"; (iii) it uses "that", not "who", to refer to chimpanzees; and (iv) it properly uses "does so" as opposed to "does that". Therefore (E) is correct.

I'm finding that the Kaplan Hard SC's are very tricky indeed!
I chose E on this one primarily because:
1. We need "exceeds" and not "exceed"
2. In the second half, "that does so" seemed to best fit "the proportion" when I scanned the answer choices.

From my understanding, in the second half, 'of chimpanzees..." is a prepositional phrase and "does so" rightly refers to the proportion. Is this reasoning correct or what am I not seeing here?

While doing this question, I couldn't help but laugh at how proportions could possibly yawn. However, I put it aside thinking that it was some grammar rule that I was unfamiliar with.

Or perhaps, 'that' can possibly refer to prepositional phrases?
If not, then perhaps logic trumps pronoun proximity?

Any thoughts?

OK, I am confused. There's a rule in GMAT Grammar Book: "If the object of the preposition is singular, use a singular verb. If the object of the preposition is plural, use a plural verb."

A high percentage of the population is educated.
A high percentage of the people are happy.
The majority of Congress has voted for the bill.
The majority of Senators have voted favorably.

Under this rule the correct version would be "the proportion of chimpanzees .. exceed" however the correct answer is "exceeds". Could anybody please clarify this concept?

Gmatdog, my brain is mush, I meant to say "the proportion of chimpanzees exceed", not the other way around (just edited my post)! Chimpanzees are a group, not a single entity hence we should use the plural form: exceed.

I guess my question is if there is a specific list of words that are "number transparent"?

Two-thirds of the work is complete.
Two-thirds of the workers are angry.

Half of the dresses are dirty.
Half of the sugar is gone.

Is "proportion" one of those words?

Can somebody elaborate whether "proportion" is singular or plural?

So far I know the following: With fractions, percentages and indefinite quantifiers (e.g., all, few, many, much, some), the verb agrees with the preceding noun or clause.
e.g. One-third of this article is taken up with statistical analysis. BUT One-third of the students have graduate degrees.

Why "the proportion of monkeys" should be singular?
Thanks
_________________

MGMAT1 - 610
MGMAT2 - 670
MGMAT3 - 640

OMG