nothing to do with trains

[whole diary]

[6 OF 2 redundant adjunct of unimatrix 01]

ok, there is a quiz every sunday at our local... at the end there is something called the ''lucky three'' basically out of the 40 questions 3 are picked and they say right or wrong... simple huh? well the argument arised what is the chance in winning the lucky three (excluding the fact that if it is a draw it rolls over)

[Mookiemoo]

ok, there is a quiz every sunday at our local... at the end there is something called the ''lucky three'' basically out of the 40 questions 3 are picked and they say right or wrong... simple huh? well the argument arised what is the chance in winning the lucky three (excluding the fact that if it is a draw it rolls over)

WHAT!

I'm a mathmeticia but I dont get the parameters!

3 Q's are picked so there is a 3/40 chance of being picked

Is there any rule about what is right or wrong?

[6 OF 2 redundant adjunct of unimatrix 01]

i think this is where the argument arrised! all the teams playing have a chance in the lucky 3 at the end... three random questions are picked (in the hat there are 80 pieces of paper for example question 1 correct and question 1 wrong and so on) what is the chance of matching correct or incorrect on the 3 questions

my friend thinks it is 1/8 (which would be correct if there were only 3 questions) but does the fact that the 3 questions are picked out of 40 change these odds?

i myself think that the chance is 1/240

[eightf48544]

Still not quite sure what you mean?

What is actually drawn out of the hat a question or an answer or question and answer?

What do you have to guess?

Also:

Are there an equal number of right and wrong pieces of paper? If not you would need to know the ratio and have to calculate the odds accordingly.

Are the questions returned to the hat after each pick,  each team or do they stay out.

If they are returned after each pick you are always selecting out of 80.

If they are returned after each team you are selcting out of 80, 79, 78.

If they are kept out it would depend on what order the teams draw the questions as you would be drawing from a dimissing pool.

As far as I can see your friend is right if there are 80 bits of paper with an equal number of right and wrong and the paper is returned after each pick. Because you have a 0.5 chance of being right on the first, 0.5 chance on the second and 0.5 on third.

Thus 0.5* 0.5*0.5 = 0.125

It's a varient on the coin tossing, but confused by the pair of socks from a drawer. For coin tossing each throw is always 50:50 no matter how many heads you've thrown before. Drawing a matching  pair of socks from a drawer with an equal number of blue and black is 3 if you don't mind  whether it's blue or black, in this case however you do mind what the answer is, so it starts at 50:50 but depending on whether the paper is replaced or not gets more complicated with subsequent picks.   

Now if the paper isn't replaced then it's still 0.5 for first go but 39/79 for second go if you are guessing your 2nd answer to be the same as the first actual or 40/79 if you are guessing the opposite to first actual answer. For the third it could be 38/78 if first two actual answers are the same as your third guess but  39/78, if the first two actual answers are different.

So still hovering around an eighth.

It gets more complicated for later teams if the paper is removed at each go. If you've guessed more of the opposite answers to those drawn so far then your odds are better  than an eigth because there are more of your answers left in the hat. Conversley if your guesses match those drawn so far there are less bits of paper with your answers in hat so the odds lengthen.

Perhaps Mookiemoo can pick holes in my logic.

[grahame]

Relex109, I'm haveing trouble working out the parameters too ... and I've done a bit of maths and stats in my time.   Googling for "Lucky Three" didn't help ... gave me so 3 minutes films and the "Lucky Three DimSum Bar" in Fall Church, Washington DC^▸ (Direct Current) ... which at least gets me back on track via the Orange line of the Washington Metro.   I'm a long way from "The West" ... but am I the only one who's got off at Rosslyn just to ride up and down the longest escalators that I know of anywhere!

If it's a question of guessing which question is pulled and in the right order, the answer is 1/40 x 1/40 x 1/40 if all three questions have to be guessed before the first draw is made, or 1/40 x 1/39 x 1/38 if the team makes a guess, a question is drawn, guesses, etc

If it's simply whether the team got three questions questions chosen at random from those asked during the quiz right or wrong, then there is easy statistical answer as it depends on the skill of each of the teams in answering the questions (i.e. the average score for the teams will be a factor) ...

[grahame]

Perhaps Mookiemoo can pick holes in my logic.

Or mine!

[6 OF 2 redundant adjunct of unimatrix 01]

at the end of the quiz three numbers relating to the quiz questions are pulled out of the hat within the hat each question has 2 pieces of paper one for correct and one for incorrect... but the same number cant be selected twice so if say for example 1 is pulled out twice first time correct and second time incorrect then the second 1 is discarded and another number drawn

[6 OF 2 redundant adjunct of unimatrix 01]

i know that if there were only 3 questions then the chance would be 1/8 as there are 8 combinations across the 3 questions

yyy
nnn
yny
nyn
yyn
nny
nyy
ynn

but is the fact that there are 40 original questions out of which the 3 are selected irelevent as my friend belives

i really have a headache over this 

[johoare]

... but am I the only one who's got off at Rosslyn just to ride up and down the longest escalators that I know of anywhere!

...sorry Grahame, but last October I stayed in Rosslyn for a week and rode the escalator ever day to get into Washington DC^▸ (Direct Current)... so you're now not the only one..

[Chris from Nailsea]

I think all of you need to get out more! 

[Mookiemoo]

Perhaps Mookiemoo can pick holes in my logic.

Or mine!

If I could understand the question I might!

[6 OF 2 redundant adjunct of unimatrix 01]

give up! 

[Mookiemoo]

give up! 

Relax - WHAT exactly happens

Are there questions in the bag or answeres?  Are there two bags - one with Q's and one with answers - because one post you made implied the Q's and answers were in ther same bag!

For things like this I am like a dog with a bone

[johoare]

OK, o I've been trying to ignore this one, but I did Maths as a degree, so now I need to know too..

We need to know more specifics... please?  well I do anyway to understand it.. 

[6 OF 2 redundant adjunct of unimatrix 01]

ok the lucky three is done after the quiz there are 40 questions in the quiz now say you answer question 4 correct question 2 wrong and question 40 wrong, if the quiz master pulled out 4 correct 2 wrong and 40 wrong you would win but if for example they pulled out 40 correct you would lose