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The Basics of GMAT Combinatorics

By: Apex GMAT Contributor: Svetozara Saykova Date: 24th June 2021 Combinatorics can seem like one of the most difficult types of questions to come across on the GMAT. Luckily there are not many of them within the exam. Still these questions make up the top level of...

When Probability Meets Combinatorics: One Problem, Two Approaches

By: Rich Zwelling, Apex GMAT Instructor Date: 16th March, 2021 Now, we’d like to take a look at an Official GMAT Probability problem to pull everything together. The following is a good example for two reasons:  1. It illustrates a quirky case that is difficult more...

An “Undesired” Approach to GMAT Probability

By: Rich Zwelling, Apex GMAT Instructor Date: 11th March, 2021 In our last post, we discussed a solution for the following question, which is a twist on an Official Guide GMAT probability problem: Xavier, Yvonne, and Zelda individual probabilities for success on a...

Combinations with Restrictions

By: Rich Zwelling, Apex GMAT Instructor Date: 4th March, 2021 In our previous post, we discussed how GMAT combinatorics problems can involve subtracting out restrictions. However, we discussed only PERMUTATIONS and not COMBINATIONS. Today, we’ll take a look at how the...

Permutations with Restrictions

By: Rich Zwelling, Apex GMAT Instructor Date: 2nd March, 2021 So far, we’ve covered the basics of GMAT combinatorics, the difference between permutations and combinations, some basic permutation and combination math, and permutations with repeat elements. Now, we’ll...

What Happens When Permutations Have Repeat Elements?

As promised in the last post, today we’ll discuss what happens when we have a PERMUTATIONS situation with repeat elements. What does this mean exactly? Well, let’s return to the basic example in our intro post on GMAT combinatorics: If we have five distinct paintings,...