The Ultimate Guide to GMAT Geometry III: Trapezoids, Rectangles, Squares

The Ultimate Guide to GMAT Geometry, Part III: Trapezoids, Rectangles, and Squares Chapter 8: Trapezoids (Trapeziums (Trapeziae?)) in GMAT Geometry If you were paying attention to the footnotes, then you’d recognize this as the extra credit answer.  In essence, a trapezoid is sort of a dodgy parallelogram, where only two of the opposite sides got … Read More

GMAT Grammar Tips for Sentence Correction: the Ultimate Guide

GMAT Grammar Tips for Sentence Correction: the Ultimate Guide GMAT Grammar is an odd concept. I mean, how could it possibly be different from normal English grammar?  HAHAHAHAHAHAHA! The problem, then, becomes one of how one defines “normal English grammar.” The problem is that there’s not really one particular type or book of grammar that … Read More

GMAT Probability Question SOLVED: An Exception to the “At Least” Rule?

A GMAT Probability Question Fully Solved: An Exception to the “At Least” Rule? It’s difficult to say that there’s really an exception–after all, you can do any Probability question multiple ways, forward, backward, or even sideways. The question is just which of these ways will be most effective in the given situation. What is the … Read More

Collapsing Probabilities in GMAT Probability: Part Deux

Collapsing Probabilities: Part Deux — for Part Un, Click Here This one I’m only doing with the “Collapsing Probabilities” technique. You’re welcome to do it by making your choice first, then multiplying by the number of potential choices. It’s just that I won’t. You can e-mail me if you need your hand held. Here’s the … Read More

Collapsing Probabilities in GMAT Probability

Collapsing Probabilities in GMAT Probability Unsurprisingly, there’s more than one way to look at this phenomenon. Let’s take a look at this straightforward case… Bag 1 contains forty marbles numbered consecutively from 11 to 50. Bag 2 contains fifty marbles numbered consecutively from 41 to 90. If one marble is selected from each bag, what … Read More

GMAT Probability: Number of Distributions x Probability per Distribution

GMAT Probability and Number of Distributions x Probability per Distribution The Independent Probability Case for GMAT Probability Now, let’s go back to the example from the previous page, which we can rephrase as this:If a coin is flipped five times, what is the Probability that it will land on Heads only once?That gives us a … Read More