According to surveys by the National Institute on Drug Abuse

[ntr1989512]

According to surveys by the National Institute on Drug Abuse, about 20 percent ofyoung 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

OA is E

the source come from prep!
in addition, i was stuck by E, since i remember ron say the form of "twice as many\much as" can only modify the noun that comes immediately before the comma. and in E "twice the number reported in the 1977 survey" is followed by "in 1979", so "twice the..."should modify 1979. it doesn't make sensebecause i think "the number" is "explicitly numerical quantity", the phrase"twice as many as" the number" should kill the "as many as" just like ron said. . so why E is right?
in order to make what i say above clear, i quote some words ron said in the some posts.

if you're going to say COMMA + "twice as many as...", then that's incorrect unless there's actually a quantity in front of the comma.
e.g.
last year i read 40 books, twice as many as i read in the preceding year
--> correct
last year the number of books i read increased dramatically, twice as many as i read in the preceding year
--> incorrect.

&

here's the basic idea:

if you say "twice as many", then this construction should be paired with a countable noun.
e.g., twice as many dogs --> "dogs" is a countable noun

if you said "twice as much", then this construction should be paired with an uncountable noun.
e.g., twice as much water --> "water" is an uncountable noun

if the noun in question is already an explicitly numerical quantity, then you should use neither "much" nor "many". instead, you should just use "twice" or "double" by itself.
e.g., twice the increase --> "increase" is an explicitly numerical quantity

these rules are followed pretty closely.
so, for instance:
twice as much water --> correct, since "water" is an uncountable noun (but is not an explicitly numerical quantity)
twice the water... --> incorrect, since water is not a numerical quantity

twice as much as the increase... --> incorrect; redundant
twice the increase... --> correct.

[tim]

Ron is saying that a number has to appear somewhere before the comma, not immediately before the comma. Thus E does not violate his rule..

[ntr1989512]

Ron is saying that a number has to appear somewhere before the comma, not immediately before the comma. Thus E does not violate his rule..

thanks tim!
but i don't grasp your idea. the problem for me is not "number" rather than "twice".
"comma+twice as much as.." just only modify the quantity noun immediately before the comma, just like ron example:
last year i read 40 books, twice as many as i read in the preceding year

but in choice E, "twice" is followed by "the number". that is ok
because i think "the number" is explicitly numerical quantity and just like ron say that:
if the noun in question is already an explicitly numerical quantity, then you should use neither "much" nor "many". instead, you should just use "twice" or "double" by itself.
e.g., twice the increase --> "increase" is an explicitly numerical quantity

if so, "twice the number..." have to modify "in 1979" that is make no sense.
please tim or ron explain more for me !i really confused about this problem.

[tim]

i had a lot of trouble following your post because of all the grammar errors, but i think you've got the right idea for the most part. you just need to remember that if you have a noun modifier, it needs a noun to modify right next to it UNLESS right next to it is another modifier of the same noun. a string of modifiers for the same noun is acceptable. does this make sense?

[ntr1989512]

i had a lot of trouble following your post because of all the grammar errors, but i think you've got the right idea for the most part. you just need to remember that if you have a noun modifier, it needs a noun to modify right next to it UNLESS right next to it is another modifier of the same noun. a string of modifiers for the same noun is acceptable. does this make sense?

I sorry for that, next time i will try to examine my saying!
i understand your idea, but i think that all examples i posted in this thread do not fit the condition you said, since there is no a string of modiders for the same noun.
i have some questions that need you clarify:
1) "twice as many as " is a noun modifier?
2) "the number of B" is not a quantity?


if 1) is right, i think 1# incorrect, since "used cocaine in 1979" is not another noun modifier. if 1) is wrong, 1# is correct, since there is a quantity:"20 percent of young adults " in front of comma.
1# According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979,twice the number reported in the 1977 survey

2#last year i read 40 books, twice as many as i read in the preceding year
---correct, since "40 books" is a quantity

3# i read 40 books last year, twice as many as i read in the preceding year
---correct, since there is a quantity: "40 books" that appear somewhere before the comma

4#last year the number of books i read increased dramatically, twice as many as i read in the preceding year
---if 2) is right, i.e. "the number of B" is not a quantity. 4# will be wrong, since there is no a quantity in front of comma! but if 2) is wrong, i don't know why 4# is wrong

5# 40 books i read last year were so fantastic, twice as many as i read in the preceding year
---- correct, since "40 books" is a quantity and appears somewhere before the comma.

if I'm wrong, please clarify me.
thanks in advance.

[tim]

i have some questions that need you clarify:
1) "twice as many as " is a noun modifier?
2) "the number of B" is not a quantity?

your first observation is correct, but i think "the number of B" is certainly a quantity..

as for your 1# observation, apparently the GMAT thinks this type of construction is okay so you just need to remember that and move on, despite the rule we usually invoke about the modifier touching the noun..

your 5# observation is incorrect; however it would be correct if you said:

"40 books i read last year were fantastic, twice as many as were fantastic in the preceding year"

note that this construction parallels the correct answer in the original problem. see if you can spot the big difference between your example and mine..

[750plus]

Can you please explain what is the problem with option D?

Is "as much as those" incorrect?
Because much cannot be used with people. Am I right?

Also, is there any other reason to eliminate?

Thanks!

[RonPurewal]

this problem is from "1000SC", which is a banned source here. thus no more further discussion of this problem.

(you should not use 1000SC in your studies! there are MAJOR issues with most of the problems in that source—essentially the only problem-free items are the ones that were stolen from GMATPrep.)