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Author Archive | Mike MᶜGarry

GMAT Math: Memory vs. Memorizing

A Case Study of the Area of an Equilateral Triangle Fact: on the GMAT Math section, you are likely to find questions about the area of an equilateral triangle, and it would be efficient if you knew the formula.  (BTW, the formula appears a little further below.)   Don’t Merely Memorize I am going to […]

Introduction to GMAT Data Sufficiency

The Old School Approach: Find the Answer In all the math you have done in your pre-GMAT life, the goal has usually been to simply find the answer.  In grade school math, high school math, and introductory college math, you are tested and graded on your ability to find the specific numerical answer to a […]

The 5 GMAT Math Formulas You Must Know and Understand

What do you need in order to excel at anything? A mastery of the fundamentals. This is true for master athletes, master artists, and great musicians. It’s also true for those who want to master GMAT math. In the math of the GMAT, certain formulas are your fundamentals. There are five GMAT formulas that you should […]

GMAT Permutations and Combinations

Permutations A permutation is a possible order in which to put a set of objects.  Suppose I had a shelf of 5 different books, and I wanted to know: in how many different orders can I put these 5 books?  Another way to say that is: 5 books have how many different permutations? In order […]

GMAT Distance and Work: Rate Formula

Formulas A rate is how fast something is growing, changing, or being performed.  The overarching rate formula is: Amount = Rate x Time   When the rate is a speed, this simplifies to the familiar formula: Distance = Speed x Time   In questions about speed, especially where an object travels at one speed for […]

GMAT Sentence Correction: Parallelism

Parallelism can come in many forms on the GMAT. Here are five famous passages: see if you can identify all the parallel structures, and below, I’ll discuss them. (Kudos, also, for recognizing the sources!)  Each quote is preceded by a difficulty rating, assessing how hard it is to identify the parallelism in that quote. The […]

GMAT Averages and Sums Formulas

Everyone knows how to find an average, but the power of this formula is often underestimated.  We know: average = (sum of the items)/(number of items) Notice, we can also write this as: sum of items = (average)*(number of items) This latter form can be powerful.  For example, if we add or subtract one item […]

GMAT Math: Area of a Triangle

As you may remember from high school, , where b is the base and h is the height.  If you are having trouble remembering this, simply remember that a rectangle has an area of  , and that a triangle is half a rectangle.     Practice Question: Using the Area Formula 1) The figure on […]

The Pythagorean Theorem on the GMAT

There’s a reason this is the most famous theorem in mathematics!  This remarkable theorem is one of the most versatile and highly adaptable formulas in existence.  Of course, I’m sure you remember that it says: For any right triangle,                       Of course, if any question […]