Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

Permutations Combinations and Anagrams

Problem Solving — algebra and arithmetic
Expert replies
by bpolley00 » Thu Dec 27, 2012 7:08 pm
Hey everyone, so far I have really struggled with Permutations, Combinations and Anagrams. Thus, I was hoping to get a forum post that was completely devoted to not only answering these questions but also doing so efficiently. In addition, I was hoping to be able to get an explanation on distinguishing these types of questions on the test. So my goal for this post is to go over what I have as far as study materials and to see if I cannot get Ron or some other expert to verify/ elaborate further, in a more concise manner.

Anagrams- These questions are usually asking for arrangements. So for example, how many arrangements of 6 books on a shelf can you make? The answer is merely 6! = 720. If you have a question that asks how many combinations of Pizzazzz can you make it would be 8!( Total number of letters)/ 5! (repeated Letters) =8*6*7=336. Another Example would be Atlanta= 7!/3!2! Which I will let you guys figure out.

Coin Flip Questions- Get K Flips out of N Flips. So what is probability that you get 3 heads out of 4 flips? The equation I have is NCK/2^n Where NCK= N!/k!(N-K)! So for this question you would have NCK= 4!/3!1!= 4 4/ 2^4= 4/16 = 1/4

Combinations- are known as unordered subgroups where basically order doesn't matter. Thus, I merely have the NCK equation So N!/K!(N-K)! Which is very similar to the coin flip.

Hard Question: A Volcano has a 50% probability in a year to erupt. What is the probability that it erupts 2 years in a 5 year period? The only way i know to solve this is with the Binomial Distribution Formula = NCK*p^k * (1-p)^(n-K)

I watched the Thursday with Ron on the Slot Method; However, I didn't really quite get it with the order does matter vs order doesn't matter.

Basically, I just need a summation of someone who is getting 100% of these questions correct to give me an explanation of exactly what approach you are taking per different questions and how you are distinguishing which approach to use, as I feel that my approach is quite formula heavy and not very intuitive.

Thanks so much for taking the time to read my post guys and I look forward to hearing your responses.
Join the discussion
Source: — Quantitative Reasoning |

by MartyMurray » Fri Nov 21, 2014 1:34 pm
To make it all more intuitive, one thing I do is just look at what's going on and, in a way anyway, create a formula myself. Yes, I already know most of the formulas I am going use. At the same time, the foundation of what I am doing is not so much memorizing formulas as understanding concepts.

For instance, in your books on a shelf example, I have the basic idea, and without memorizing a formula I realize that I can choose from six books to put in the first slot on the shelf. That starts the arrangement six different ways.

Then for the next slot there are five choices left. So I started six ways and for each of those six ways I have five choices for the next slot. Already we have 6 x 5 = 30 different arrangements.

This goes on for the next four slots, and for each there are fewer books to choose from, and I end up doing just what you said, 6! = 6 x 5 x 4 x 3 x 2 x 1, except I didn't exactly memorize a formula. Rather I knew how it worked in reality, and applied that to basically create the 6!.

Now if there is some twist in how the arrangement is to be made, maybe a certain book has to be first, I just change my math to fit that twist and create a formula or set of formulas that will get me to the answer.

That's the general idea with these questions. There is a logic to how they get answered, and rather than just memorizing formulas, you can apply that logic to quickly come up with a formula that fits a particular situation.
Join the discussion

by 009hnoor » Wed Apr 29, 2015 1:08 am
Then for the next slot there are five choices left. So I started six ways and for each of those six ways I have five choices for the next slot. Already we have 6 x 5 = 30 different arrangements.
Join the discussion