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ELIMINATION!!!

GMATMONSTER ENCOUNTER MANY LINEAR EQUATION SYSTEMS ON GMAT. ELIMINATE CONSTANTS! ELIMINATE VARIABLES! HERE EXAMPLE:

4x+3y=57
7x+6y=108

SUBSTITUTION BAD METHOD. ME PROVE IT:

4x+3y=57
3y=57-4x
y=19-4/3 x

PLUG IN HERE:

7x+6(19-4/3 x)=108
7x+114-8x=108
-x=-6
x=6

MANY FRACTIONS! CAUSE MESS-UPS. BETTER METHOD IS ELIMINATION, ME SHOW YOU. FIRST, GMATMONSTER MULTIPLY ONE OR BOTH EQUATIONS BY WHATEVER NUMBER CONVENIENT. THIS TIME CONVENIENT NUMBER IS 2.

4x+3y=57
7x+6y=108

(2)(4x+3y)=(2)(57)
7x+6y=108

8x+6y=114
7x+6y=108

NOW GMATMONSTER HAVE 6y IN TOP EQUATION AND 6y IN BOTTOM EQUATION. NOW COME FAVORITE PART. ELIMINATION!!! GMATMONSTER ELIMINATE 6y TERM BY SUBTRACTING BOTTOM FROM TOP.

(8x+6y)-(7x+6y)=114-108
x=6

THIS EASIER! NO FRACTIONS! NO MESS-UPS! LINEAR EQUATION SYSTEMS ARE NO MATCH FOR STRATEGY OF ELIMINATION!!!

2 days ago • Algebra, GMAT Quant

2

Studying Gerunds Will Help You on the GMAT

The -ing suffix comes up often in my GMAT classes as a point of confusion. In the context of the GMAT, I group such words into three broad categories:

    1. Gerunds:

      Flying is fun.
      I am tired from flying.

      Gerunds function as nouns. It’s important to understand when you are dealing with gerunds on the GMAT, because they can function as singular subjects that have verbs associated with them. Without understanding this, you might think “Flying airplanes are fun” is a legal sentence, because even “airplanes” looks like the plural subject of the verb “are.” However, in this case “airplanes” functions as an adjective(!) and “Flying” is the noun, so “are” should be changed to “is.”

    2. Modifiers:

      The airplanes flying from Los Angeles have been delayed.
      Flying in formation, the pilots dazzled the crowd.

      These -ing words are what we commonly think of as participles. You can think of them as any -ing word that gives us more information about something else (“flying from Los Angeles” describes/modifies “The airplanes”). It’s ok in this example to say “Los Angeles have been delayed” (as opposed to “Los Angeles has been delayed”) because “The airplanes” is the subject of the verb “have.” We know this because the participle “flying” introduces the modifying phrase.

    3. Verbs:

      I am flying from Los Angeles to New York.
      I have been flying for ten years now.

      4. “Flying” here is still technically a participle, but on the GMAT, I like to distinguish between this construction and the modifier construction. The difference is the helper verbs: “I am flying” and “I have been flying.” The former constitutes progressive tense, the latter perfect tense. This is relevant to the GMAT because tenses that share a subject must make sense. That’s a whole separate topic, but suffice it to say that it’s usually not a good idea to think about the participle itself in this case – it’s better to think about the whole construction as a single unit.

4 days ago • Modifiers, Sentence Correction

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Similar Situations

I enjoyed this post from EvalBlog highlighting how when you change a shape’s length and width by a certain percentage, the area changes by a different percentage.

It turns out that this is relevant to the GMAT! Think of a square with an area of 1 square unit and side lengths of 1 unit. If you quadruple the area, the side length doubles, and you end up with a square that has an area of 4 and side lengths of 2. But what happens to the side lengths when you double the area? In other words, if a square has an area of 2, what is the lengths of each side? Or to complicate matters, if circle A has area x and perimeter y, and circle B has area 9x, what is the perimeter of circle B in terms of y? You don’t need the circle area formula to figure this one out – this trick works for any similar figures!

17 days ago • Apocrypha

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Warning: Babies Make You Poor

One of the major U.S. presidential candidates recently stated, “If you graduate from high school, you get married before you have children, and of course you work – that’s sort of a given, you have to work – you do those three things, there’s a 2 percent chance you’ll be in poverty.” He has made similar claims during various speeches or debates, but there’s a problem; the study he cites, done by the Brookings Institution, ascribes only correlation and not causation. This candidate completely ignores the very real possibility that poverty causes dropouts, children out of wedlock, and unemployment.

If you are given a critical reasoning question on the GMAT, please do not make this mistake. Here’s how such a GMAT question might be phrased:

In addition to the Brookings Institution study, what information would be most helpful in informing new policies to combat poverty?

A). A study of the best setup for “safety net” programs to ensure that high schoolers don’t drop out.
B). A study of methods to eliminate childcare tax breaks for unmarried taxpayers.
C). A study of the most effective policies for combat unemployment in recent years.
D). A study that determines whether jobs are less available to those already in poverty than to the rest of the population.
E). A finely granulated study of graduation rates across the United States.

If you get this one right, you may be qualified to run for president.

19 days ago • Apocrypha

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Study Plan

There’s a really great rundown of GMAT study advice today on the Manhattan GMAT blog. It covers what to do if you are running out of time, what to do if you have hit a wall, what to do if you are shooting for the 98th/99th percentile, and other frequent scenarios. Check it out when you want to kick-start your study routine!

39 days ago • Apocrypha

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MEAL OF BURRITO

GMAT MONSTER HUNGRY, GO TO CHIPOTLE. ALLOWED 1 CHOICE OF 4 MEATS (CHICKEN, STEAK, CARNITAS OR BARBACOA), 1 CHOICE OF 4 SALSAS (FRESCA, CORN, GREEN OR RED), AND ANY CONDIMENTS OUT OF 6 AVAILABLE (RICE, VEGGIES, BEANS, SOUR CREAM, CHEESE, LETTUCE).

If GMAT Monster wants 1 meat, 1 salsa, and any number of condiments on his burrito, how many burrito variations does he have from which to choose?

More

40 days ago • Combinatorics, GMAT Quant

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BRAND DESTRUCTION

GMAT MONSTER WATCH SPORTING EVENT AND SEE LUXURY AUTOMOBILE ADVERTISEMENT.

GMAT MONSTER FILLED WITH RAGE AT GRAMMATICAL MISTAKE. DOORS COUNTABLE SO SPEAKER PERSON SHOULD SAY “FEWER DOORS” INSTEAD OF “LESS DOORS.” WHAT IS THIS, KIA COMMERCIAL???

46 days ago • Sentence Correction

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Joe’s Dog

The topic of modifiers always seems to be the most troublesome for my GMAT students. Modifiers are really important on the GMAT, and I can give you a simple example to convince you that you should study them. Consider this sentence:

Joe walked the dog in the park.

This sentence has a critical problem. Have you spotted it yet? More after the break.

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46 days ago • Modifiers, Sentence Correction

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ME CHAMPION OF GMAT

ME GMAT MONSTER. ME SCORE 101ST PERCENTILE ON GMAT BECAUSE NO HUMAN PERCENTILE GOOD ENOUGH TO REPRESENT SCORE. ME GO TO INSEAD, FAMOUS SCHOOL OF BUSINESS. ME GOOD FIT FOR INSEAD BECAUSE NAME IN ALL CAPS. ASK ME QUESTIONS ABOUT GMATS!

50 days ago • Apocrypha

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Hi, I’m Ryan!

I scored in the 99th percentile on the Graduate Management Admission Test (GMAT). Now I teach and tutor for Manhattan GMAT. I started teaching the GMAT after I graduated with my MBA from the Rady School of Management at UC San Diego. Welcome to my blog!

50 days ago • Apocrypha