Blog (Free Videos!)

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

How to Understand GMAT Factorials

How to Understand GMAT Factorials — the Three-Question Method If we don’t get the concept of Factorials straight, the rest of this–Permutations and Combinations, quite a lot of advanced GMAT fatoring, etc.–is never going to work. How to Think About GMAT Factorials in a Broad Sense The idea of a Factorial is best described as … Read More

The Real World versus GMAT Critical Reasoning

                                        There isn’t really much relationship between GMAT Critical Reasoning and the Real World GMAT Critical Reasoning questions are extremely tightly-constructed little logic bombs that have nothing to do with the Real World. While it’s not pleasant to have to say this, I think it’s … Read More

How to Analyze GMAT Quant Questions Properly PART II

CONSISTENTLY ASK YOURSELF: “Am I spinning my wheels?” Remember, that means doing things that won’t get you to the answer any faster. Are you calculating something that won’t yield one of the five answer choices? That’s not to say that the GMAT is giving you wrong information, but rather that the answer choices restrict your … Read More

How to Analyze GMAT Quant Questions PROPERLY

Arithmetic–or calculation for calculation’s sake–is a waste of time on GMAT Quant Questions. ​ There–I said it. Allow me to add a premise to my argument: insecurity plays a huge role in GMAT Quant Questions. Chew on that for a moment, and let this sink in: Already the human computer is widely displaced by mechanical … Read More