The correct answer is 75%.

You have a total of eight different possibilities:

4-0 in favor of Team A
4-1 in favor of Team A
4-2 in favor of Team A
4-3 in favor of Team A
4-0 in favor of Team B
4-1 in favor of Team B
4-2 in favor of Team B
4-3 in favor of Team B

So the total number of choices for the game to end with less than 7 games = 6 different possibilities

Therefore % less than 7 games = 6/8 = 75%

Hi Mathew,

We can not use binomial probability theorm here. Because in order to use the binomial theorm, the number of trial (or games in this example) should be fixed. In this case, the number of trials (games) are not fixed. It depends on the outcome of each game. For example if team A wins all the first 4 games, then the series ends there..no further games. I think rkrish7's answer 75% is the correct answer.

Thanks

I opened a discussion here:

http://www.baseballprimer.com/clutch/ar ... l#comments

Here's what I think is the right answer:

<i>12.5% of the time the series will end in 4 games. (2 in 16)
25% of the time the series will end in 5 games. (8 in 32)

62.5% the series doesn't end in 4 or 5. That means it MUST be 3-2 after Game 5.

Which means half the time, Game 6 is the last game and it end 4-2.

Which means that 31.25% of the time, the series will end in 6 games.

12.5% + 25% + 31.25% = 68.75%, what I said earlier.

That leaves 31.25% of the time for it to go 7 games.

Am I being totally obtuse? It's possible. </i>

This was a tough question. Thanks to all of you who put up a great effort!

My apologies! Will put down a footnote next time.

btw: the url is: http://www.manhattangmat.com

thanks all!

Hey, AkamaiBrah, You wrote that:

"I would prefer that you did not post them at all.

In any case, you are NOT allowed to post the solution as it is private and reserved for the use of our clients. (The solution is password protected and available by subscription only. If you are one of our clients, I don't think Zeke would approve of you sharing his challenge problems and solutions with the world)."

http://www.manhattangmat.com/ChallProbLastWk.cfm

Well, it might be "private" and "reserved for the use of (your) clients", and the solution might be "password protected" and "available by subscription only", but absolutely anyone can get access to the solution for free, as long as he or she furnishes or fabricates an email address. It's not like Titleist has taken a for-pay part of the site and redistributed it.

I am neither a lawyer nor an ethcist, but I fail to see any problem or harm if he takes a free question and reposts it with proper attribution.
If I'm off base, please tell me why.

First of all, thank you Titliest for promising to respect the copyright of Manhattan GMAT. I apologize if I came across as a hardass.

Let me address a couple of points:

1) Access to the solutions is not "free" but granted in exchange for your e-mail address. Just because you are not required to pay any money for something, does not make it free. There is an intangible "cost" to you for providing such information and certainly a "value" for MGMAT to obtain it. By publicly posting the solutions, you circumvent the right of MGMAT to receive "payment" for their intellectual property.

2) Copyright protection applies regardless of whether material is "free" or for pay. The network broadcast of a concert is free, but it would be illegal for me to incorporate any significant portion of it in my own work and redistribute it -- with or without attribution -- without express permission from the copyright holder.

3) While publishing other people's works in part with attribution is ordinarily acceptable (though often abused), publishing other people's works in toto certainly is not. Since MGMAT publishes just one problem per week, I can see a scenario where every problem and solution is published every week, essentially replicating the entire series of problems on a 3rd-party forum. That would not be cool.

4) Just because digital media makes it easy to duplicate and republish material, does not make it right.

While I cannot speak for the owner of MGMAT, IMO an acceptable way to post a challenge question is:

"I found this week's Manhattan GMAT challenge problem interesting and would like to share it with you:"

At which point, the forum is free to discuss the problem and post solutions in their own words. Those who want access to the official solution are welcome to subscribe to the service.

Finally, those of you who have been long time members of this forum may note that some of the challenge problems I post are indeed those from ManhattanGMAT. This is because I compose many of the MGMAT challenge questions and I use this forum as a "test bed" before submitting them to Manhattan GMAT for use on their web site. Hence, you already have VIP access to a significant number of the Manhattan GMAT challenge questions and solutions -- long before anyone else in the world. I am willing to continue doing this so long as the users of this forum will respect my copyright, and the copyright of MGMAT once any problem is published on its website.

Thank you.
_________________

Best,

AkamaiBrah
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993

AkamaiBrah,

First, I want to say thank you for clarifying your point. I also want to thank you and Manhattan GMAT for coming up with the most challenging questions I have seen from any other test prep service. I appreciate your presence here in this forum as a value-added resource. I will go ahead and post the weekly challenge problems in the format you have described (if I'm so compelled to do so). What drives me crazy about the M.G. weekly challenge problems is that after I take the usual => 2 mins to solve the problem, I have to wait a week for the answer.

Titleist

True. Even when I do come to an answer that I'm reasonably sure about, I still want to know for certain if it's correct. BTW, are these questions that much harder than the 700 level questions on the actual GMATs? Thanks again!