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## Topic review (newest first)

mathsyperson
2005-07-14 02:01:06

I'm not sure, but looking at the user list tells you that it's somewhere between 196 and 286.
I'm guessing 200.

mathsyperson
2005-07-14 01:57:25

You've done at least 30 posts.

mathsyperson
2005-07-14 01:38:10

You did your 5th post.

mathsyperson
2005-07-07 03:19:17

Randomly pick one. The remaining papers will have one matching letter and three pairs of different letters. This means that for the first pair there is a 1 in 7 chance of them matching.
For the second pair, the same reasoning applies except that there are now only two pairs of different letters so there is a 1 in 5 probability of them matching.
The third pair has a 1 in 3 chance and if all 3 of these pairs match then the last pair must also match.
The total probability is worked out by multiplying all of these together, so it is 1 in (7x5x3x1) or if you want to be really technical, 1 in 7!!, which works out to be 1 in 105.

iamstuck
2005-07-07 02:51:08

please can somebody help me understanding the maths to work out the probability of :-

if i had eight identical pieces of paper, 2 of which had the letter A written on them, 2 with B, 2 with C
and 2 with D written on them , jumbled up upside down on the table . if i was to randomly arrange them into pairs what would the probability be of ending up with AA BB CC DD ?