There are hopeful signs that

[licampus2019]

In the 1980’s the rate of increase of the minority population of the United States was nearly twice as fast as the 1970’s.

(A) twice as fast as
(B) twice as fast as it was in
(C) twice what it was in
(D) two times faster than that of
(E) two times greater than

You had explained why C is the answer and rest are wrong.
So, Does the "it" refer to "THE RATE OF INCREASE OF XYZ?"
[yes, it does. --ron]

1. Hi,Ron,If "it" refer to "the rate of inrease of xyz" in the example above,how can not "it" refer to "the quality of las vegas" in the example below?

The difference between the two examples is the positon of "in the 1980's" and "in 2007".
Maybe "1980's" modify the whole sentece,not "the rate of...",can explain?

2. If "it" can refer to "the air quality of las vegas",can we replace "that" by "it":
the air quality of las vegas in 2007 was higher than it in 1997

Please throw some light on the problems above,thanks.

* the air quality of las vegas in 2007 was higher than that in 1997
--> CORRECT
note the perfect parallelism
(the air quality of las vegas) (in 2007)
parallel to
(that) (in 1997)

[mschwrtz]

If "it" refer to "the rate of inrease of xyz" in the example above,how can not "it" refer to "the quality of las vegas" in the example below?

The difference between the two examples is the positon of "in the 1980's" and "in 2007".
Maybe "1980's" modify the whole sentece,not "the rate of...",can explain?

That's it exactly. In the 1980's modifies the clause the rate ... was nearly twice.... While of Las Vegas is an essential modifier of the quality.

[jazeltq]

B is wrong because it does not necessarily refers to energy only, but refers to more than ten times as much energy...now, how can we say the energy generated...now is as much as it(the energy generated...now) was in 1990?

I recalled one question that is similar to this one just for reference.

Over 75 percent of the energy produced in France derives from nuclear power, while in Germany it is just over 33 percent.

A. while in Germany it is just over 33 percent
B. compared to Germany, which uses just over 33 percent
C. whereas nuclear power accounts for just over 33 percent of the energy produced in Germany
D. whereas just over 33 percent of the energy comes from nuclear power in Germany
E. compared with the energy from nuclear power in Germany, where it is just over 33 percent

OA is C

eliminate A, because it refers to over 75 percent of the energy produced in France, not the energy only.

in the same way, the energy in C,D,E refers to the same precedence as A. so eliminate C,D,E

hope it can help

nice find!

both this problem and the problem in the thread are examples of the important principle that when a pronoun stands for a noun to which ESSENTIAL MODIFIERS (i.e., modifiers without commas) are attached, the pronoun must STAND FOR THE NOUN PLUS ALL ESSENTIAL MODIFIERS attached to the noun.

does it make sense ?

[jazeltq]

great example ron..

if in your above example, i write
the air quality of las vegas was higher in 2007 than that was in 1997...is it parallel?

if it is not, please give an example how to make this example parallel

actually, there is no way to make this example work -- you cannot use "that" as a pronoun by itself. you can only use "that" as a relative pronoun when it is part of a parallel construction (e.g., "that of...", "that in...", "that used by...").

in general, i don't think that you can ever use "this", "that", or "those" as standalone pronouns. (i have, however, seen a single instance of "these" as a standalone pronoun, in one GMATPREP problem.)

what about this ?
the air quality of las vegas was higher in 2007 than was that in 1997...is it parallel?

[RonPurewal]

what about this ?
the air quality of las vegas was higher in 2007 than was that in 1997...is it parallel?

that's still not good, since you have "that in 1997", but you don't have "the air quality of las vegas in 2007"; that latter construction is broken up by a verb. so there isn't really anything to which "that in 1997" would be properly parallel.

in other words, incorrect for the same reason that the second example in the following post is incorrect:
post39671.html#p39671

[yklouk]

Instructors, I wonder whether I could move away "was the case":

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

Is the sentence above still correct? two adverbial phrases are in comparison: now and in 1990.

[tim]

no..

[yklouk]

no..

Umm...But for this sentence I met in prep, two adverbial phrases are comparing: In no other historical sighting did Halley’s comet cause such a worldwide sensation as in its return of 1910-1911.
why we could omit "subject + verb" in this sentence, but couldn't in this thread's question?

the following sentence also shows highly succinct:
According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.
why should we add "was the case" before in 1990, or could we just insert the helping verb "was" between as and in 1990?

[RonPurewal]

Instructors, I wonder whether I could move away "was the case":

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

Is the sentence above still correct? two adverbial phrases are in comparison: now and in 1990.

that's not correct, because you need an explicit tense change. this is the purpose for "...was the case" in the correct version here: it changes the tense from "is generated" (present tense) to "was the case" (in 1990).
if you don't have that explicit tense change, then the sentence is still talking in the present tense (which is nonsense if you're referring to something that was true in 1990 and has since changed).

[RonPurewal]

no..

Umm...But for this sentence I met in prep, two adverbial phrases are comparing: In no other historical sighting did Halley’s comet cause such a worldwide sensation as in its return of 1910-1911.
why we could omit "subject + verb" in this sentence, but couldn't in this thread's question?

right -- note that there is no tense change here.
if you added a verb, you'd have
in no other sighting did the comet cause ... as it did in its return ...
that's why the verb is unnecessary here; it would be the same helping verb in the same tense.

more analogues:

i can run as fast on grass as on concrete
i can run as fast on grass as i can on concrete
--> both correct (no tense change)

but...
i can run as fast now as in high school --> incorrect, since i'm not in high school anymore.
i can run as fast now as i could in high school --> correct, with the necessary tense change.

the following sentence also shows highly succinct:
According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.

same deal.
no tense change, so you don't need to repeat the verb.

[yklouk]

Awe inspiring! thanks a million, Ron.

[jnelson0612]

:-) Ron always inspires my awe! :-)

[raheel11]

i could've sworn this problem was in another thread, but the search box won't find it.

there are two splits you should use to narrow down this problem:

(1) the second half of the construction 'ten times as much ... ____' is as, not than. therefore, you can eliminate answers (a) and (e), which contain 'than'. (i'm assuming that (e) is supposed to say 'than', not 'then'; i don't think the gmat problems would that blatant an error)

(2) the pronoun 'it' is inappropriate, because 'it' must refer to the ENTIRETY of the noun phrase serving as an antecedent.
for instance, the following is an improper sentence: last year's attendance was ten thousand greater than it was this year
in the above sentence, the pronoun 'it' must necessarily refer to last year's attendance, not just attendance.
the problem in this post has the same issue: the pronoun 'it' must refer to more than ten times as much energy, not just energy - an interpretation that makes no logical sense. therefore, all answer choices containing the pronoun 'it' are wrong.

if you don't like '...than was the case', you should learn to like it; this is one of those phrases that the gmat writers use to refer to concepts that don't fit under the usage constraints of traditional pronouns. (another popular one of these constructions is 'do so'.)

Awesome explanation !!

[RonPurewal]

Awesome explanation !!

thanks.

[swapna]

B is wrong because it does not necessarily refers to energy only, but refers to more than ten times as much energy...now, how can we say the energy generated...now is as much as it(the energy generated...now) was in 1990?

I recalled one question that is similar to this one just for reference.

Over 75 percent of the energy produced in France derives from nuclear power, while in Germany it is just over 33 percent.

A. while in Germany it is just over 33 percent
B. compared to Germany, which uses just over 33 percent
C. whereas nuclear power accounts for just over 33 percent of the energy produced in Germany
D. whereas just over 33 percent of the energy comes from nuclear power in Germany
E. compared with the energy from nuclear power in Germany, where it is just over 33 percent

OA is C

eliminate A, because it refers to over 75 percent of the energy produced in France, not the energy only.

in the same way, the energy in C,D,E refers to the same precedence as A. so eliminate C,D,E

hope it can help

nice find!

both this problem and the problem in the thread are examples of the important principle that when a pronoun stands for a noun to which ESSENTIAL MODIFIERS (i.e., modifiers without commas) are attached, the pronoun must STAND FOR THE NOUN PLUS ALL ESSENTIAL MODIFIERS attached to the noun.

Hi Could you help me explain why D is incorrect in this example?