1 hour Combinatorics Video Lesson

Question

For anyone struggling to understand combinatorics and how this concept may show up on the exam, please learn these critical insights:

It is broken down as follows:

00:00 - Intro
01:00 - Warmup
02:12 - Part 1 Overview: Combinations & Permutations vs Variations
08:35 - Part 1 Details: Picking Teams, Dice, Pocket Pair, Dating
17:21 - Part 2: Apply to GMAT - Word Problem #1
22:13 - Part 2: Apply to GMAT - Word Problem #2
31:34 - Part 2: Apply to GMAT - Word Problem #3
38:04 - Part 3: Poker Probability - Pocket Pair vs Pocket Aces
43:40 - Part 3: Poker Probability - Given Pocket Aces, 3-of-a-Kind?
46:13 - Part 3: Poker Probability - 1-Pair by 5th Flop
49:59 - Part 3: Poker Probability - Full House/Flush
1:00:00 - Conclusion

Note: the Poker part is just for fun - you will not see poker questions on the test. But the prior 3 examples are game for the test.

pacifist85 · Answer

That wasn't very useful for me... You actually need to know quite a bit first in order to follow the video.

Bunuel · Answer

Combinations and probability are advanced topics. One should deal with them only after all other topics covered by the test. Also, before attempting questions, one should go through basics. Theory on Combinations: math-combinatorics-87345.html DS questions on Combinations: search.php?search_id=tag&tag_id=31 PS questions on Combinations: search.php?search_id=tag&tag_id=52 Tough and tricky questions on Combinations: hardest-area-questions-probability-and-combinations-101361.html Theory on probability problems: math-probability-87244.html All DS probability problems to practice: search.php?search_id=tag&tag_id=33 All PS probability problems to practice: search.php?search_id=tag&tag_id=54 Tough probability questions: hardest-area-questions-probability-and-combinations-101361.html Hope it helps.

mischiefmanaged · Answer

I am stuck with 3 problems and the way they are solved:

1. How many distinct ways can 3 guys vote for those 3 girls? (variations)
Solved by considering the 1st guy can date 3 girls, 2nd guy can date 3 girls as well ...
3*3*3 = 3^3

2. How many potential dates can happen between 3 guys and 3 girls? (combinations)
3c1 + 3c1 + 3c1 = 9

3. How many different ways can 3 guys and 3 girls pair up for a group date of 6 people? (permutations)
3c1 * 2c1 *1c1 = 6

Can someone please help me understand what is the difference between the 3, as it is all about 3 guys choosing 3 girls, and why different methods are used

patto · Answer

I think this video is extremely helpful. Thank you Zeke! for making it available.  GMATPill .
First time I find something really useful on combinatorics

LucasSimon · Answer

the GMATpill website doesn't seem to be working. Does anyone know about this?

UzairSohail · Answer

This video is not available now. How can we access it?

courty · Answer

Could this video please be made available again? If not are there any alternatives you would suggest?

aasdf1234 · Answer

To all who stumble upon this thread only to realise that the main video posted by GMATPill isn't available, I suggest watching this video https://www.youtube.com/watch?v=redKVdUhO44 which is hosted on GMATClub's YT channel.

MJ15 · Answer

Hi there,

can someone please help me find the link for below video sequence ?

Rinka · Answer

where is the video?

Bunuel · Answer

The video is no longer available. Archiving the topic.

1 hour Combinatorics Video Lesson

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