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#101 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 21:20:50
Ok so basically you are dealt 4 cards, out of the 4 cards, 3 of them have different suits and different values but the last one is either the same suit/value as one of the three. What are the odds of this?
I think you misread the question before.
#102 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 21:08:12
Yea so my logic is that the first card will always be 100% correct, the next card has a probability of 36/51, and the third will be 22/50, but the fourth has to be the compliment so 42/49. Does that make sense?
#103 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 20:49:39
It does not specify so i assumed that 3 different values, while the 4th card can be the same value as one of the 3.
#104 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 20:42:03
Yes I dont know why we havent been taught Generating Functions but for now this will do. Ok so I have a doubt about one of my answers, the question is:
In the game of Badugi, the goal is to get 4 cards that have different suits and different values. Such a hand is called a Badugi.
What is the probability that you are dealt a 4-card hand that contains 3 cards of different suits and different values, but is not a Badugi?
I divided this into 3 cases where, first case is whee the second card is either the same suit or the same value as the first
second case is where third card is the same suit/value as 2nd or 1st card.
third case " " fourth card is the same suit/value as one of the 3 cards.
Am I thinking this through correctly?
#105 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 20:13:37
Sorry i meant post# 14
Yes its 9 choose 2.
Thanks a lot bobbym!! I can get some sleep now 
Its been bugging me since friday!
#106 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 20:08:50
Yes but I will have to review tomorrow morn after a good nights sleep 
btw reread post# 12
Also I still need help with the proof by induction on n on:
#107 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 20:03:00
Yup got it thanks!! 
#108 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 19:58:12
GAH!!! OK makes sense! This is what happens at 4 am in the morning .
ok so we have
now thats accounting for all the possibilities where the letters can go...how do we account for the order? and the 2Ds?
PS OH!!! 5! is the possibilities to arrange 5 letters and then divide by 2! to account for Ds!! THANKS!!! !!!!
WOOT!
#109 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 19:50:42
Wouldnt that just be 8 choose 2? As i am only selecting any 2 slots out of the 8 slots to put the balls in?
#110 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 19:43:14
is it not
?I am comparing this to lets say putting n balls into 4 boxes....
i.e. n = 10
0001001000100
0s represent balls and 1s represent the slots
so its
then similarly
5 letters in 8 boxes....oh wait theres a limitation here that each box can only contain 1 or 0. Hmm, so no I dont understand how you get that.
#111 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 19:30:47
Yes I have studied polynomial multiplication but I do not get how you got that equation for G(x). Also how are the 2 Ds handled here, if they are switched is this another combination or is it counted as 1? If it is counted as just one(as is what i need) then I do not understand how your calculations incorporate that.
#112 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 19:12:16
Umm is there another way because I havent studied Diophantine equations nor generating functions. 
Sorry for the trouble
but thanks!!!
#113 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 18:41:15
I dont want the answer, I want to know the logic behind the answer so for future reference i know how to get it. So can please explain how you got 47520?
#114 Re: Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 17:58:33
for the first question my answer was:
#115 Help Me ! » Perms and Combs! and some induction.. » 2011-05-29 17:54:28
- careless25
- Replies: 101
Ok so I have been working on this question for more than 8 hours in total...I cannot get it outta my Head so someone explain this to me!
How many arrangements of the word INDEPENDENCE are there? How
many such arrangements have the property that all the Ns come before all
the Es? (For example, CNNDNEEEPIED is one of them.)
Part 1 of the question is easy, its the Ns before the Es thats giving me a headache.
I eventually got to this:
My reasoning is that theres 5 letters that can be placed anywhere: IDPDC
4 Es which come before the 3 Ns
So I made 6 cases, one where all the Ns are the first 3 letters, so i get (9!/(4!2!)) combinations.
second case: 3Ns and 1 extra letter, which gives me: 8!/(3!2!)
third case: 3Ns and 2 letters and so on and so forth
until i get a total of 77220
but then i realized I over counted many many combinations and I gave up at this point
OK thats that question...another one i need help with is:
(n C r) notation means n choose r...
but then again i get stuck in the induction step.
Any help ASAP is appreciated!!
Thanks a lot
#116 Re: Help Me ! » Calculus I help! » 2010-10-07 00:05:18
Thanks a lot both of you ...
Soroban thats a nice trick...took me a few minutes to understand but finally got it
#117 Help Me ! » Calculus I help! » 2010-10-04 12:54:52
- careless25
- Replies: 3
Heres the question i cannot solve:
sin x + 8 cos x represented in the form Asin(x-y)
Thanks,
C25
#118 Help Me ! » Vectors and Planes » 2010-04-08 12:43:06
- careless25
- Replies: 2
I have a math mid-term tomorrow and I cant do these from the Review. Can you solve/explain them to me ASAP?
1. Determine the components of a vector of length 44 that lies on the line of intersection of the planes with equations 3x - 4y + 9z = 0 and 2y - 9z = 0.
2. The line through a point P(a,0,a) with direction vector (-1,2,-1) intersects the plane 3x + 5y + 2z = 0 at point Q. The line through P with direction vector (-3,2,-1) intersects the plane at point R. For what choice of a is the distance between Q and R equal to 3?
3. Consider the two lines:
L1: (x,y,z) = (2,0,0) + t(1,2,-1)
L2: (x,y,z) = (3,2,3) + s(a,b,1)
where s and t are real numbers. Find a relationship between a and b (independent of s and t) that ensures that L1 and L2 intersect.
For this one, I get the right answer but I m not sure if my method is correct.
I take the 2 points given and subtract them and find the direction vector (1,2,3).
I also take the 2 direction vectors given and subtract them to obtain (a-1,b-2,2).
I make x1=x2, y1=y2, z1=z2.
I get:
a-1 = 1
a = 2
b-2 = 2
b = 4
3 = 2??
and a = 1/2 b is the answer.
4. In the following system of equations, k is a real number.
-2x + 4y + z = k + 1
kx + z = 0
y + kz = 0
a. For what valuess of k does the system:
i) have no solutions?
ii) have exactly one solution?
iii) have an infinite amount of solutions?
Thank you for your help!
C25
#119 Re: Help Me ! » solve my code please! » 2010-01-09 06:47:55
Hi John,
Nice! I have seen this done once before and it is a good way to encrypt. I think periodic table idea might be able to solve it. There are soo many combinations you can try here. How about setting the numbers into a square or rectangle then convert to periodic table and then take the letters or groups of letters out in vertical rows.
for e.g.:
i e v m
l p e u
i i r c
ke y h
take the letters out in vertical rows you get ilikepieverymuch or i like pie very much. I might try this later busy with finals right now.
C25
#120 Re: Help Me ! » solve my code please! » 2010-01-07 10:57:16
I've now linked to it...thanks!
no problem. Its useful for soo many things.
Right there with you, there is some evidence to support this. But they are not going to release it to us, so as far as mathematics is concerned the factorization of 200 digit composites that are made up of 2 100 digit primes is intractable. Even if some clever guy figured how to factor that 200 digit composite in say a year or so with a super computer, all anyone who have to do is provide a new key consisting of a 300 digit composite, to make the method secure again.
I use wolfram alpha all the time and so should every one else! Glad to see someone else knows about it to.
Agree with you as well. I m so annoyed by the information being hidden. I can see why it is hidden but the discovery is as momentous in mathematics. But it should be hidden...maybe not!
wolfram alpha is a very good site but its got very little attention. I think it should be well known then we might see major improvements in it. I like how they implemented METs to calculate weight loss and other health related stuff. I think i found out about it 6-7 months ago...when it was quite new and then i completely forgot the name so i stopped using it for a few months. But it took a few random google searches to find it. Now its like an everyday toy and tool.
africanmiss,
this code is proving very difficult to solve but i m not giving up...yet!
C25
#121 Re: Help Me ! » solve my code please! » 2010-01-06 15:31:39
Bobbym i dont think he would have given out an encrypted message to someone that cannot be decrypted by the person. What would be the point of it? And i believe the firend is trying to get africanmiss interested into cryptology so the message must decrypt.
We just have to wait for someone/people to find a way to find prime integers easily then RSA is possible to crack. And it might already be done by some secret agency.
C25
Edit: I actually know a site that does prime factorization quite fast for the number of digits that are provided in this puzzle.
Check out http://www.wolframalpha.com
#122 Re: Help Me ! » Mode help?! URGENT » 2010-01-06 12:56:31
For these set of numbers all the numbers are the mode.
C25
#123 Re: Help Me ! » solve my code please! » 2010-01-06 12:52:48
africanmiss/ malawimiss
i come to the same conclusion as bobbym but i havent tried too much on it yet. It is definetly going to take some time to break.
I will check my cryptology book for more info on a code like this and get back to you.
O and one more thing, he might have used yours or his name and that could come in handy if provided. I know this is personal info and you may want to keep it out of public forums so i will understand if you don't provide it.
You could still provide how long the name is e.g. 5 letter, 6 letters...
C25
#124 Re: Help Me ! » solve my code please! » 2010-01-04 14:09:44
Hey africanmiss!
i am also going to try and solve your code. But i have a few questions about it. How did you come about the code? What did you do to solve it?
and your post was most likely deleted from the coders corner because coders corner is only for programming(coding).
C25
#125 Re: Jokes » Daddy How was i Born? » 2009-12-22 18:32:31
Once you have the baby all that is immaterial Tigeree.