Joined: 11 Aug 2012
Location: United States
Concentration: Strategy, Marketing
GMAT Date: 10-12-2012
WE: Project Management (Energy and Utilities)
, given: 21
COMPARISONS : QUESTION KILLER : A COMPILATION [#permalink]
11 Oct 2012, 10:50
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Comparisons are the most frequent topic on GMAT. The best part about comparison based problems is that they are very easy to spot.
Comparisons basically is the discussion of similarities or differences between two elements (people, places, things or ideas)
• Like, as, compared to, contrast, different from, unlike.
• Larger, slower, higher, colder, highest, slowest.
The law of comparison is that it must be logical and it must be ambiguity free.
Consider the sentence:-
• The laws in Pakistan are more restrictive than India.
Laws in Pakistan ------ India (Incorrect)
• The laws in Pakistan are more restrictive than laws in India.
Laws in Pakistan ------ Laws in India (Correct)
• Unlike India, China’s economy is primarily based on manufacturing.
India ------ China’s economy (Incorrect)
• Unlike India’s economy, China’s economy is primarily based on manufacturing.
India’s economy ------- China’s economy (Correct)
• The population of India is more than Indonesia.
Population of India --------- Indonesia (Incorrect)
• The population of India is more than that of Indonesia.
• The population of India is more than the population of Indonesia.
Population of India --------- Population of Indonesia (Incorrect)
• In addition to having more teeth than a piranha has, a barracuda’s teeth are larger than a Piranha does. ( Incorrect )
• In addition to having more teeth than a piranha has, a barracuda has teeth that are larger than a Piranha’s teeth. ( Correct )
• Max dislikes broccoli more than his girlfriend. (Incorrect)
• Max dislikes broccoli more than his girlfriend dislikes broccoli. (Correct)
• Max dislikes broccoli more than his girlfriend does. (Correct)
• The chemical engineering certification process in Peru is more time consuming than Brazil. (Incorrect)
• The chemical engineering certification process in Peru is more time consuming than that in Brazil. (Correct)
Replace Noun elements in comparison by :- that, those, it.
Replace Verb elements in comparison by :- do, does, so.
• Maple trees shed their autumn leaves earlier than oak trees. (Incorrect)
• Maple trees shed their autumn leaves earlier than oak trees do. (Correct)
• Sanjay is smarter than any student in his class. (Incorrect)
• Sanjay is smarter than any other student in his class. (Correct)
• Usain Bolt runs faster than anyone. (Incorrect)
• Usain Bolt runs faster than anyone else. (Correct)
LIKE Vs As Vs Such as
1. Use Like to compare NOUNS.
2. Like followed by a clause is wrong usage.
3. As is followed by a clause or a verb.
• Whitney sings like an angel. (Correct)
• Whitney sings like an angel does. (Incorrect – an angel does is a clause, not a phrase)
• Barry sings as a professional playback singer sings. (Correct)
• Barney collects stamps as his father does. (Correct)
• Carl curses like a lumberjack working in the woods. ( notice that no verb follows like; working in the woods is a participial phrase modifying the Noun lumberjack. This usage is correct).
• Barney loves his dogs (as/like) he loves his friends. ( Since the verb loves follows, like cannot be used. “As” is correct)
Always search for verb following like / as usage.
• He acted ( like/as ) a fool at the party that his girlfriend threw for him. ( Like is correct because relative clause that…..him modifies the Noun : Party. So no verb is being compared and hence no verb follows the phrase after like. “He acted like a fool…….” )
Like means similar to and such as is used to give examples. But still check the entire meaning of the sentence.
• I enjoy listening to bands such as COB, Megadeath, COF. (Correct)
• Barney enjoys visiting world capitols like Rome and Paris. (Correct)
JUST LIKE and SO AS TO are always wrong on GMAT.
So …X… as to (CORRECT).
GMAT mostly uses these five words for comparisons
• As (Correct)
• Like (Correct)
• Unlike (Correct)
• Just as …so (Correct) IS A COMMON WAY ON GMAT TO WRITE LONGER COMPARISON OF CLAUSES.
• So X as to (Correct)
• Just Like (INCORRECT)
Usage - Compared to/with for STATISTICS:
If you say "compared with/to" for statistics, you should cite BOTH statistics in the comparison.
The expression "compared to/with" does NOT imply any sort of direction to the comparison; i.e., it gives no hint as
to greater/less/like/unlike. Therefore, you need to give both of the relevant statistics, or else the statement won't
make any sense.
• "The unemployment rate in Esteria last month was 5.3%, compared to the rate in Burdistan."
INCORRECT! This makes no sense. We have absolutely no idea what is going on with the rate in Burdistan.
• "The unemployment rate in Esteria last month was 5.3%, compared to a rate of 7% in Burdistan."
CORRECT. Both statistics are cited.
COMPARISON OF QUANTITIES
Usage: Double / Twice / Twice as many / Two Times / Doubling
"Twice" CANNOT function as an object of the preposition such as "by".
"Twice" is an adverb.
• "... increased by more than twice ..." -- WRONG!
Relate Quantities by Multiplying
When I say “that car is nearly three times as old as you,” I’m making a comparison with numbers using multiplication. Make sure that when we use the word “times” to denote multiplication, we also use the “as…as” comparison structure:
• Incorrect: That car is nearly three times older than you.
• Correct: That car is nearly three times as old as you.
Reserve the “than” comparison for other forms; when using multiplication, stick with the “as…as” structure.
Alternatively, you can also denote multiplication when you leave out “as:”
• Correct: A gallon of milk now costs $6, three times the cost fifteen years ago.
Relate Quantities by Addition/Subtraction
For addition or subtraction, use more than/less than.
• Incorrect: Molly is five years as old as you.
• Correct: Molly is five years older than you.
Quantitative Comparisons without Numbers
When using the words more or less without numbers, you have many options to choose from. Notice that the words “more” and “less” can be used as many different parts of speech.
• Correct (as noun/pronoun): I owe you more than I’d like to. (Here, more stands in for money, or whatever it is that I owe).
• Correct (as adverb): I drive more than I’d like to. (Here, more modifies “drive;” that is, it tells me how I am driving, so “more” functions as an adverb).
• Correct (as adjective): I have more money now than I’ve ever had. (“More” describes money, so it functions as an adjective).
The words “high” and “low,” and “higher” and “lower,” by contrast, should only be used as adjectives.
• Correct: My expectations are much lower than they were five years ago.
• Incorrect: I owe you lower than I did last year. (use “less” instead)
More Vs. Greater
When something countable increases, we use “more”
• Holland has more tulips than does any other country in Western Europe.
Tulips are separate: you can count how many tulips you have.
When something uncountable increases, we also use also “more”
• The US State of Georgia has more land than does the state of Pennsylvania.
• It costs more to go to the ballgame than to go to the opera.
In #1 Land is an uncountable noun, and in #2, the implicit noun is “money”, which is also uncountable.
The question arises: when do we use “greater” rather than “more”?
We use “greater” when the noun in question is a number. We can count the number of tulips, but a tulip itself is not a number.
Some examples of nouns that are themselves numbers are: percent, interest rate, population, volume, distance, price, cost, and number.
• The area of Georgia is greater than that of Pennsylvania.
• The price of a trip to the ballgame is greater than the cost of a night at the opera.
• Call option premia are greater when interest rates are higher.
(Notice, for certain economic quantities, we will use “higher” for an increase.) In general, things take “more” but numbers take “greater.” The “increasing” case is the easier of the two cases.
Less Vs. Fewer
The confusion of “less” and “fewer” is very troubling. This is also tested frequently on GMAT.
When something uncountable decreases, we use “less”:
• Pennsylvania has less land than does Georgia.
• I have gotten less water in my basement since sealing the windows.
When something countable decreases, we use “fewer”:
• Female drivers tend to get fewer speeding tickets.
• My dorm had fewer international students.
• When fewer people are unemployed, the interest rates tend to rise.
• If you were rich, would you have fewer problems?
It’s quite possible that some of those, or even all of those, “sound” wrong. Many many people would make the mistake of using the word “less” in those sentences even though the word “fewer” is 100% correct. If you can count it, you need to use “fewer” instead of “less.” In other words, whenever you would use “how many?” instead of “how much?”, you need to use “fewer” instead of “less.”
When we compare numbers, and numbers decrease, we can simply go back to using “less.”
• The population of Mongolia is less than that of Los Angeles.
• The cost of a night at the opera is less than total cost of a day at the ballgame.
• The melting point of zinc is less than that of copper.( BTW, “melting point” is a temperature, so it is indeed a number.)