The number of people flying first

[ghong14]

Folks, I'm trying to determine if there are still questions here that need answers. If you still have questions, please post (without including official GMAT questions, please; they are a banned source).

Jaimie, I think this might have to do with one of the previous posts on this page. My question is, in general what are we looking for when there is a comparison structure that utilizes the "that of" construction? For example,

There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than 10 times as much energy is generated through wind power now than that was generated 1990.

Would that be correct? Would "that" correctly refer to energy?

[RonPurewal]

Would that be correct? Would "that" correctly refer to energy?

no, you can't have a verb in the part qualifying "that". i don't know how to explain this with terminology (nor would it help you if I did), so i'm just going to throw some examples at you.

The protein in milk and eggs takes humans longer to digest than that in whey.

The protein in milk and eggs takes humans longer to digest than does that in whey.

(both fine -- the "does" helps to add clarity here, but it's not necessary because the sentence is already unambiguous without it)

notice, the purple things correspond to each other. there's no verb in the purple thing.
it's possible for the greater comparison to contain verbs (like the blue verbs in the example above), but, as you'll notice, those verbs are not part of the "that of".../"that in".../etc. type of construction.

and, of course, you sometimes have these kinds of comparisons with no verb:
Stanford's endowment is larger than that of any other university.

[ghong14]

no, you can't have a verb in the part qualifying "that". i don't know how to explain this with terminology (nor would it help you if I did), so i'm just going to throw some examples at you.

Is this because putting a verb after that destroys the parallel structure of the sentence? Because it doesn't seem to...........

There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than 10 times as much energy is generated through wind power now than that was generated 1990.

That refers to energy ONLY right? Not 10 times as much energy?

[RonPurewal]

ok, let me try this from another angle, because that's still an ungrammatical construction.

when you use this kind of "that" in a comparison, it's a pronoun.
if you try to stick a verb after it, you get an entire sentence (subject+verb) stranded within the middle of a larger sentence; that doesn't work.

in other words, if you take out "that" and put in the noun it's trying to stand for, the sentence woud still work.

take my example:
Stanford's endowment is larger than that of any other university.
Stanford's endowment is larger than the endowment of any other university.
... so this is kosher.
(don't worry about "the"; that's not tested on this exam, and it won't ever be.)

let's try that with yours. (i'm going to assume you meant to write "in" before "1990".)
more than 10 times as much energy is generated through wind power now than that was generated [in] 1990.
more than 10 times as much energy is generated through wind power now than energy was generated [in] 1990.

that latter thing isn't a sentence, because "energy was generated in 1990" is already a sentence.

that's about the best i can do with regard to explaining this. if this still isn't clear to you, i'd suggest forgetting about "rules" and just looking at the patterns in a large number of correctly written comparison sentences. then it should all make more sense.
(this is how the human brain wants to learn language anyway: by recognition and imitation, not by "rules". you'll find that things become much easier if you follow that tendency, rather than trying to resist it.)

[HanzZ]

by the way, you can strike (d) and (e) without even seeing the prompt.
as soon as you see "twice as many as the increase...", these choices are automatically incorrect (since "increase" is not a countable quantity).

---
Hello Ron,

Can we also eliminate d and e on the grounds that there is simply nothing to be parallel with "the increase' after the parallel marker?

Also for a, at first I was thinking, hmmm there is nothing to match 'increase'. Then I realize it's not even a parallel structure. Anyway, the out-of-blue 'increase' is kinda weird to me. Could you please help?

Thanks in advance!

[HanzZ]

by the way, you can strike (d) and (e) without even seeing the prompt.
as soon as you see "twice as many as the increase...", these choices are automatically incorrect (since "increase" is not a countable quantity).

---
Hello Ron,

Can we also eliminate d and e on the grounds that there is simply nothing to be parallel with "the increase' before the parallel marker?

Also for a, at first I was thinking, hmmm there is nothing to match 'increase'. Then I realized that it's not even a parallel structure. Anyway, the out-of-blue 'increase' is kinda weird to me. Could you please help?

Thanks in advance!

[RonPurewal]

You can't argue that "increase" itself is sketchy. Not only is it in the correct answer, but it's in all five options. (The first part of the sentence describes an increase, so there's no sketchiness at all.)

On the other hand, if you are purely asking about "filling in the blanks" in a structure such as ______ is twice as much as ______ -- and not referring to whether the idea of "increase" is sensible -- then, yes.

[ghong14]

Looking at the original problem how does this differ from the following which is also a GMAT prep problem?????

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.

according-to-surveys-by-the-national-institute-on-drug-abuse-t15511.html

Wouldn't A be the correct choice considering that the two sentences share the same structure. Twice would violate the noun modifier rule as you stated:

f 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.

&



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.

[RonPurewal]

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.

according-to-surveys-by-the-national-institute-on-drug-abuse-t15511.html

"Those" would have to be "young adults", so choice A implies that something is "doubling" those young adults.
That's nonsense. You can double the number of young adults, but you can't "double" the young adults themselves.
You can only double quantities, amounts, or other numerical things. You can't "double" a physical entity.

An "increase" is a numerical quantity, so "doubling the increase" makes perfect sense.

[RonPurewal]

Wouldn't A be the correct choice considering that the two sentences share the same structure.

Officially correct answers are correct!
Do not question them!

Don't fight the official answers. Complete waste of time.

"is this correct?" is never a productive question to ask about one of GMAC's correct answers. The answer is always yes.

"is this wrong?" / "is this X type of error?" is never a productive question to ask about one of GMAC's correct answers. The answer is always no.

Instead, the questions you should be asking about correct official answers, if you don't understand them, are:
"Why is this correct?"
"How does this work?"
"What understanding am I lacking that I need to understand this choice?"

This is a small, but hugely significant, change to your way of thinking. You will find it much easier to understand the format, style, and conventions of the official problems if you retire the idea that they might be wrong.

Twice would violate the noun modifier rule as you stated:

No. The idea directly in front of the comma is a statistic (In 1979, 20 percent of xxxx people did blah blah blah). 20 percent is a numerical quantity.

last year the number of books i read increased dramatically, twice as many as i read in the preceding year
--> incorrect.

This is incorrect because there's no actual number mentioned before the comma, so "twice as many..." is not actually describing anything.

[RonPurewal]

Finally, regarding this:

Looking at the original problem how does this differ from the following which is also a GMAT prep problem?????

"?" is enough.
"?????", which is the internet equivalent of screaming and throwing a tantrum, is just plain rude.

From now on, just "?", please.
Thanks.

[soulwangh]

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.

according-to-surveys-by-the-national-institute-on-drug-abuse-t15511.html

"Those" would have to be "young adults", so choice A implies that something is "doubling" those young adults.
That's nonsense. You can double the number of young adults, but you can't "double" the young adults themselves.
You can only double quantities, amounts, or other numerical things. You can't "double" a physical entity.

An "increase" is a numerical quantity, so "doubling the increase" makes perfect sense.

Hi Ron，

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.

What about if I change "doubling" to "double" in the following sentence? In other words，I change double from a verb to a predeterminer as same as is "twice". Is it correct?

According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, double the number reported in the 1977 survey.

Thanks in advance!

[soulwangh]

Hi Ron，

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.

What about if I change "doubling" to "double" in the following sentence? In other words，I change double from a verb to a predeterminer as the same as is "twice". Is it correct?

According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, double the number reported in the 1977 survey.

Thanks in advance!

Hi，Ron

According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, doubling the number reported in the 1977 survey.

I use a participle here.
Can you help explain whether this sentence is correct？

Thanks!

[RonPurewal]

No, because "doubling xxxx" means that xxxx itself is actually raised to 2 times its original value.

The number from the 1977 survey is not going to change anytime after 1977, so that doesn't make sense.

(E.g., Smith hit 50 home runs this season, doubling his career total.
--> This makes sense. Previously, Smith's career total was 50 home runs. Now, his career total is 100 home runs.)

[manhhiep2509]

"in this case, you can't use "..., twice as many as...", because that's an appositive modifier. appositives must modify some noun that comes IMMEDIATELY before the comma, which in this case would have to be whatever figure is twice whatever other figure. since no such figure is given, you can't use this construction. "

Ron: Can you plz explain above paragraph for me with an example?? I can NOT understand this rule applied in this question.

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

Hi Ron.

Can "Comma + twice as many as" and "Comma + twice the number" modify entire preceding clause as does the abstract noun, i.e. discovery, in the below example?

Or do the two structures, not only the former, only refer to explicitly numerical quantities?

scientists found fossils of X, a discovery that has stirred the science community.

------

ok, let me try this from another angle, because that's still an ungrammatical construction.

when you use this kind of "that" in a comparison, it's a pronoun.
if you try to stick a verb after it, you get an entire sentence (subject+verb) stranded within the middle of a larger sentence; that doesn't work.

in other words, if you take out "that" and put in the noun it's trying to stand for, the sentence woud still work.

take my example:
Stanford's endowment is larger than that of any other university.
Stanford's endowment is larger than the endowment of any other university.
... so this is kosher.
(don't worry about "the"; that's not tested on this exam, and it won't ever be.)

let's try that with yours. (i'm going to assume you meant to write "in" before "1990".)
more than 10 times as much energy is generated through wind power now than that was generated [in] 1990.
more than 10 times as much energy is generated through wind power now than energy was generated [in] 1990.

that latter thing isn't a sentence, because "energy was generated in 1990" is already a sentence.

you said:

more than 10 times as much energy is generated through wind power now than energy was generated [in] 1990.[/i]

that latter thing isn't a sentence, because "energy was generated in 1990" is already a sentence.

So, if the above sentence is incorrect, then the below are also incorrect, aren't they?

"in the country, as many people like to read books as people like to watch TV"
"as many people like to read books in country X as do people in country Y"