As stated in GMAT SC - Use Logic, the pool of required grammar knowledge for the GMAT is likely shallower than you would think; those who memorize hundreds of idiomatic rules or read the cover off of their copy of Strunk & White’s “Elements of Style” are studying counter to the real purpose of the GMAT’s inclusion of Sentence Correction: the idea of “core competencies.” Corporate Strategy courses in business school will spend quite a bit of time on that notion that each business needs to recognize the handful of things it does extremely well and find opportunities to leverage that. When businesses stray from their core competencies they tend to struggle mightily, throwing away resources and providing diminishing returns with increased risk.
For example, McDonald’s has a set of core competencies that allow it to run extremely efficient fast-food operations in high-traffic areas. It’s natural, then, to acquire Chipotle and replicate the same processes with a different type of fast food; if McDonald’s were to try to distribute its products through the frozen foods aisles at grocery stores, however, it might find that it’s ill-equipped to compete with that different set of core competencies. Businesses specialize, and as a potential Master of Business you should specialize, too. Don’t try to memorize everything there is to know about grammar; learn to recognize the common GMAT decision points and you can efficiently make the decisions that you’ve trained yourself to make effectively.
Verbs make fantastic decision points, as they are involved in subject-verb agreement errors, verb tense errors, and comparison errors (are we comparing an action to an action?). Pronouns also lend themselves well to decisions, as they can disagree in number or they can fail to refer to anything specific. When you look at the answer choices of a sentence and see the same verb in different forms or a choice between singular and plural pronouns, you should immediately identify those as classic decision points and look to make your choices there. Similarly, as comparisons are often tested on the GMAT, the presence of pronouns like “that of” or “those of” should indicate that you need to decide whether the comparison requires such a possessive:
Q) The question of whether to allocate a portion of their salaries to retirement plans is particularly troublesome for recent college graduates, whose salaries are typically lower than senior members of companies; with the rising cost of living, younger employees often struggle with having to pay bills while trying to save for the long run.
B) than those of
C) than is so of
D) compared to
E) compared to those of
Here, the presence of “those of” in B and E should tip you off – we need to determine whether we are comparing X with Y or something that belongs to X with “those of” Y. Going back to the sentence, we see that we’re comparing “salaries” belonging to recent graduates to… “senior members of companies”. Which is illogical— we can’t compare salaries to people; it has to be salaries to “those of” the other people. So we must have either B or E. E is redundant — “lower” already tells us that we’re comparing, so adding “compared to” just adds unnecessary words, and so B is the correct answer.
Knowing that “those of” triggers an important decision point, you can avoid reading most of this sentence – you know what you’re looking for and you can quickly dive into that decision, saving valuable time for later problems on the test.