Learn how to talk about quantities in comparisons on GMAT Sentence Corrections
There’s actually a math question on the GRE entitled “Quantitative Comparison“, an alternative math question that resembles nothing asked on the GMAT. This article is not about that at all. This article is about GMAT Verbal questions: specifically, Sentence Correction questions in which numerical quantities are discussed and compared.
Some things in life (cars, cats, houses, lawnmowers, etc.) come in countable units. The hallmark of countable nouns is that we would ask “how many?” — how many cars? how many cats? etc. — to ask about them.
Some things in life (air, water, pleasure, pain, science, art, money, etc.) come in varying quantities but have no countable units. Rather, these things come in what you might call uncountable bulk. The hallmark of uncountable nouns is that we would ask the question “how much?” (How much air is in that tire? How much pain was he in? How much science does she know?) to ask about them.
This distinction between countable vs. uncountable will be important below.
Getting bigger: more vs. greater
When something countable increases, we use “more”:
1) Holland has more tulips than does any other country in Western Europe.
Tulips are distinct and countable: you can count how many tulips you have.
When something uncountable increases, we also use also “more”:
3) It costs more to go to the ballgame than to go to the opera.
“Land” is an uncountable noun, and, in #3, the implicit noun is “money”, which is also uncountable (as opposed to units of money, such as dollars, which are countable).
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.
4) The area of Georgia is greater than that of Pennsylvania.
5) The price of a trip to the ballgame is greater than the cost of a night at the opera.
6) Call option premiums 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.
Getting smaller: less vs. fewer
I will warn you: we are coming up on one of the most frequently made mistakes in spoken English. Even otherwise highly literate and intelligent people routinely make this mistake. Yet, the GMAT will penalize you for making this mistake. It’s the confusion of “less” and “fewer.”
When something uncountable decreases, we use “less”:
7) Pennsylvania has less land than does Georgia.
8) I have gotten less water in my basement since sealing the windows.
OK, now get ready for the mistake-zone. When something countable decreases, we use “fewer”:
9) Female drivers tend to get fewer speeding tickets.
10) My dorm had fewer international students.
11) When fewer people are unemployed, the interest rates tend to rise.
12) 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.”
By the way, the winner for the all-time most widespread grammatically incorrect sign: “ten items or less”. How many times have you seen that grammatical error at the grocery store?
Mercifully, when we compare numbers, and numbers decrease, we can simply go back to using “less.”
14) The cost of a night at the opera is less than total cost of a day at the ballgame.
15) The melting point of zinc is less than that of copper.
BTW, “melting point” is a temperature, so it is indeed a number.
The more of these rules you remember, the greater the number of GMAT SC questions you will get correct (in less time) and the fewer mistakes you will make!