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An SC doubt.

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by gmat_perfect » Sun Mar 13, 2011 8:49 pm
According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, doubling those reported in the 1977 survey.

(A) doubling those reported in the 1977 survey
(B) to double the number the 1977 survey reported
(C) twice those the 1977 survey reported
(D) twice as much as those reported in the 1977 survey
(E) twice the number reported in the 1977 survey

My explanation:

"20% of young adults" is countable.
Example:

number of young adults is 100.
So, 20 young adults.

The sentence stands:

20 young adults used cocaine in 1977, ...............

We can easily eliminate B and D. I am in confusion about A and C. Since 20 adults is plural, the use of "those" seems correct.

Would any one explain?

Thanks.
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Source: — Sentence Correction |

by tetura84 » Sun Mar 13, 2011 10:50 pm
doubling of what?
Is it the percentage or the young adults?
Definitely the percentage.

Lets have an example.
in 1977, out of 100 young adults, 10 used cocaine = 10%
in 1979, out of 150 young adults, 30 used cocaine = 20%
So, percentage is doubled without doubling the no of young adults.
A, C, E out.

Between B and E, B uses COMMA+INFINITE = this is wrong.
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by gmatmachoman » Sun Mar 13, 2011 10:58 pm
Identify the subject :

20 percent is the singular subject.

"of young adults "-- Prepositional phrase. Its just a filler-- ignore it

So the modifier is supposed to modify the subject

In E , the modifier , twice the number reported in the 1977 survey exactly modifies the subject 20 percent

Pick E

My trick is always look for the subject & verb. Then look for modifiers.

For ur info u can check out Og 11 SC No .4. It also tests the same concept
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by gmat_perfect » Mon Mar 14, 2011 12:11 am
gmatmachoman wrote:Identify the subject :

20 percent is the singular subject.

"of young adults "-- Prepositional phrase. Its just a filler-- ignore it

So the modifier is supposed to modify the subject

In E , the modifier , twice the number reported in the 1977 survey exactly modifies the subject 20 percent

Pick E

My trick is always look for the subject & verb. Then look for modifiers.

For ur info u can check out Og 11 SC No .4. It also tests the same concept
Thanks man. Your idea is good. I will see the sc you referred.
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by gmat_perfect » Mon Mar 14, 2011 12:28 am
In case of "X% of Y" whether the whole of "X% of Y" will be singular or plural depends on Y.

==> If Y is singular "X% of Y" is SINGULAR.
Example:
10% of the CD has been played. [CD is singular, so 10% of Y is SINGULAR.]

==> If Y is PLURAL, "X% of Y" is PLURAL.

Example:

10% of the songs have already been played. {Songs is PLURAL, so 10% of Y is PLURAL.}

Thanks.
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by AIM GMAT » Mon Mar 14, 2011 3:00 am
about 20 percent of young adults used cocaine in 1979 = some number lets say 20 % of 1000 = 200


200 , twice the number reported in the 1977 survey .


IMO E.
Thanks & Regards,
AIM GMAT
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by tetura84 » Mon Mar 14, 2011 3:29 am
First, subject is not 20 percent BUT 20 percent of young adults. = and the subject is not singular.
We have two flavors,
X of Y and X% of Y
In case of X of Y = verb should agree with X - "of Y" is modifier here.

But in case of X% of Y = verb should agree with Y, if Y is countable, verb should be plural, if Y is non-countable, verb should be singular.
examples:
15% of the athletes in the contest were using performance-enhancing drugs. --> plural verb, because athletes is countable
15% of the machine's output was thrown into the scrap pile. --> singular verb, because 'output' is uncountable
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by Jim@Grockit » Mon Mar 14, 2011 9:45 am
Just a reminder that the aggregate measures of things are usually singular and uncountable, even if the individual things measured are plural and countable. Just because You started with $20 and spent $15 doesn't mean you have fewer cash because you know that the remaining five dollars are plural and countable.
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by GMATMadeEasy » Mon Mar 14, 2011 12:08 pm
According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, doubling those reported in the 1977 survey.

(A) doubling those reported in the 1977 survey
(B) to double the number the 1977 survey reported
(C) twice those the 1977 survey reported
(D) twice as much as those reported in the 1977 survey
(E) twice the number reported in the 1977 survey
AT GMAT_Perfect: What is the OA please ?

C,D and E can not be OA because twice can not be used so far away from what it is modifying .

Also, "20 percent of young adults " should be plural because :

1> When X of Y in which X is a quanity expresion, Y decides whether the subject is singular or plural.

An overwhelming proportion of women -> plural (GMATPrep)

Please share your thoughts , if needed, we call an expert.
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by force5 » Mon Mar 14, 2011 2:30 pm
i Agree to E.... what is the OA?
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by atulmangal » Mon Mar 14, 2011 8:08 pm
Jim@Grockit wrote:Just a reminder that the aggregate measures of things are usually singular and uncountable, even if the individual things measured are plural and countable. Just because You started with $20 and spent $15 doesn't mean you have fewer cash because you know that the remaining five dollars are plural and countable.
Jim, thanks for your post

please suggest, m i thinking in the wright direction??

As u said that, the aggregate measures of things are usually singular and uncountable.

Does that mean,
20% of young adults -----> singular (aggregate measure) ??

Secondly, the example given by GmatMadeEasy,

An overwhelming proportion of women -> plural (GMATPrep)

This is plural because we don't know what proportion????
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