Leon: Originally I asked many friends for advice about what guides I need
for the GMAT. Some of them recommended me the GMAT Pill. I wasn’t sure
what it was, so I decided to look into it. I found a lot of comments
about how GMAT Pill was much better at explaining test strategies and
developing understanding on specific types of questions, all of which
seemed pretty attractive to me. But I also thought what was even
better was that the program was not made out of a long, strenuous
course like that in Kaplan and ManhattanGMAT. I finally made the
decision that the GMAT Pill would probably be the most efficient way
to improve my score. In the end, I have to say I made the right
decision. I don’t think the amount of effort I put in if I were in
either Kaplan or ManhattanGMAT would have allowed me get the score
that I want.

Leon: I do study everyday but rarely do I spend the entire day studying. The
good thing about GMAT Pill is that it breaks down the course into
question segments. This way, I can actually tackle the problem one by
one. The other good thing is that since the question usually comes
from a general strategy, once you get the hang of it, you can answer
that particular question type easily.

Leon: I was very weak in sentence correction. I was never really strong in
grammar. However, the GMAT Pill covered everything that I needed to
know in the test. During the actual test, every question that I came
across I had already reviewed in the GMAT Pill section. I guess
initially I was a bit skeptical whether the GMAT Pill could have
covered all the stuff I needed to know, but as I started to answer the
questions in the Official Guide I realized all the concepts were
already taught to me by the program. Without it, I would have probably
done a horrible job on the test.

Leon: When I first decided to take the GMAT, I took a few practice GMAT
tests to see where I stood. After scoring in the low 600s, I realized
I needed to improve significantly if I desired to get into the top
business schools. I was very weak in verbal and I was doing decent in
math. Knowing that I need to improve my verbal in order to really
stand out, that’s when I decided I needed a prep course. With that in
mind, at the time I was also very busy so I did not have a lot of
time.

In the end, I was quite impressed with the program and especially
loved how much improvement I made using the program in such a short
amount of time. We are all busy and sometimes we just can’t spend too
much time studying the test. But with GMAT Pill I didn’t have to
sacrifice my score for the lack of time.

I also really liked the video segments. I can always rewind back and
forth so I never get lost in a question. It is also done in a very
clean, organized way so I can see very easily how Zeke breaks down the
question and uses specific concepts to solve it. I also find this
extremely helpful because I ended up doing the same thing Zeke did
while I was taking the test-breaking it down, taking the right
approach at the problem, etc etc. I think he is really good at helping
you to figure out the best ways to identify the problem and solve it.

I think that is really the best that anyone can ask for. Sure, this
program probably won’t guarantee everyone to get a 750, but Zeke
really does a good job making you realize that the GMAT is not as hard
as you think once you know what to tackle.

OK, so he didn’t quite get the $50,000 MBA scholarship—-yet. But hey, how can you go wrong with a 750?

So congratulations to Mr. Leon Yang on this hot shot score!

This means this is a “1 – probability()” question…this is the default strategy when a question is asking the probability of at least X happening. It translates into 1 – probability(that event NOT happening)

Step 2:
Now you need to find the probability of not getting a pair for each of the 4 cards. Recognize that as you go through each card, the number of available cards from the remaining deck is constantly changing. Originally you have 12 cards, but then after you put down 1 card, u have 11 cards left.

Step 3:
1st card = any card = prob of 1 or 100%
2nd card = any card except the value of first card = 10 out of 11 choices
3rd card = any card except first card and except second card = 8 out of 10 choices
(notice we must exclude the 1st card and the 2nd card–but also the corresponding pairs for each of these cards.
4th card = any card except first/second/third card (and their corresponding pair card) = 6 out of 9 choices

Now multiply these probabilities so you know what the probability of NOT getting any pairs for all 4 iterations.
10/11 * 8/10* 6/9 = 480 / 990

1 – 480/990 = 510/990 = 17/33

Answer choice is C (17/33)

I don’t recommend using the nCr formula here, but if you want to use nCr’s, then:

= 1 – prob(choosing all different cards
= 1 – prob(choosing 4 different cards out of 6) * (possibilities for first card to be of two suits, for second card to be of two suits, for third card to be of two suits, and for fourth card to be of two suits)
= 1 – (6c4 * 2 * 2 * 2 * 2) / (12c4)
= 1 – (15 * 16) / (( 12 * 11 * 10 * 9 )/(4*3*2*1))
= 1 – 240 / 495
= 255/495

= 51/ 99
= 17 / 33

But again, this is not the most efficient way to think through this question. The best way is to count according to the method I discussed first above.
_________________
———————
Zeke Lee
Co-Founder, The GMATPill Study Method

http://www.gmatpill.com

98%ile GMAT in 2 weeks