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Augustus DeMorgan made many valuable contributions to [#permalink]
21 Sep 2012, 22:40

3

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

52% (01:49) correct
48% (00:49) wrong based on 125 sessions

Augustus DeMorgan made many valuable contributions to calculus, trigonometry, algebra, and logic; but perhaps his most famous academic contribution, a pair of theorems concerning complementation of sets, is still known today as DeMorgan’s Rules.

a.a pair of theorems concerning complementation of sets, is

b.a pair of theorems concerning complementation of sets, are

c.two theorems that have to do with complementation of sets, are

d.two theorems that define complementation of sets, is

e.two theorems that are both related to complementation of sets, are

Re: Augustus DeMorgan made many valuable contributions [#permalink]
22 Sep 2012, 04:17

5

This post received KUDOS

Expert's post

The subject ‘contribution’ plays a key role in deciding the answer here. First being a singular subject, the subject’s verb also should be singular –i.e.: is, dismissing B, C and E. Second, the singular subject entails a singular appositive modifier, namely, a pair as in A and not two theorems as in D. Hence A . _________________

Re: Augustus DeMorgan made many valuable contributions [#permalink]
23 Sep 2012, 07:47

I chose A for the following reasons: 1. the Qn has non-essential modifier marked with ",". Thus we can disregard it. Subject contribution, verb is known as contribution is singular. Options A and D left; 2. Verb define in option D changes the meaning the sentence - we don't know for sure, whether they defined or concerned complementation of sets. Option A left.

Re: Augustus DeMorgan made many valuable contributions to [#permalink]
26 Aug 2014, 14:38

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: Augustus DeMorgan made many valuable contributions to [#permalink]
27 Aug 2014, 20:36

daagh wrote:

The subject ‘contribution’ plays a key role in deciding the answer here. First being a singular subject, the subject’s verb also should be singular –i.e.: is, dismissing B, C and E. Second, the singular subject entails a singular appositive modifier, namely, a pair as in A and not two theorems as in D. Hence A .

I am confused with choosing A or D. It helps me answer my question. Thank your for exp. +1 kudos _________________

......................................................................... +1 Kudos please, if you like my post

gmatclubot

Re: Augustus DeMorgan made many valuable contributions to
[#permalink]
27 Aug 2014, 20:36