Guys, a simple math question not related to poker
 

Wrong forum but if I could just get a quick answer that'd be great. I contribute a lot of content so...

Let's say I've got a test with 13 possible essay topics. The prof will assign 5 of them, of which I can choose one. How many do I have to prepare to make it statistically like 90% that I get one that I can do?

First one who tells me gets $1 shipped to acct of their choosing.

Love,

Borntarun

Re: Guys, a simple math question not related to poker
 

number you have prepared versus percent chance he picks five from 13 without picking one you have prepared:

one 62%
two 36%
three 20%
four 10%
five 4%
six 2%


edit. I think I fixed it. don't count on me to have it right--but to inspire someone to correct me. I often screw it up.

Re: Guys, a simple math question not related to poker
 

so there are (13 choose 5) combos the prof can choose = 1287

and you're screwed only if he chooses 5 that you don't know. and you wanna be screwed < 10% of the time.

so we want (x choose 5) / (13 choose 5) < 0.10

where x is how many you don't know, and x choose 5 is how many ways you can get screwed.

(9 choose 5) / (13 choose 5) = 0.0979020979

13-9 = 4 is my answer

Re: Guys, a simple math question not related to poker
 

Should do 4 to guarantee 90%.
1-[(9/13)(8/12)(7/11)(6/10)(5/9)]=0.903

Re: Guys, a simple math question not related to poker
 

As always theres more then math to the question... you should be able to predict which topics the professor is more likely to put on and also which essays have the most overlap and are therefore less likely to BOTH be on the exam.

Re: Guys, a simple math question not related to poker
 

come on I'm not that big of a fish as to not know that... but this particular professor is a real oddball - i predicted last time and I literally got the 6 that I thought werne't gonna be on it... so i gotta just do math with this guy. thanks for all the help guys.

Re: Guys, a simple math question not related to poker
 

I like the way OP thinks!

Re: Guys, a simple math question not related to poker
 

haha nice

Re: Guys, a simple math question not related to poker
 

ok, i realized it was 15 questions... i 'm really math retarded (hence why i suck at poker). how does the math change?

Re: Guys, a simple math question not related to poker
 

You should do 9 to be 100%....