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Sounds like that is correct.. but I have no idea how to count the number of occurrences that has both fish and rat inside 26 length | Sounds like that is correct.. but I have no idea how to count the number of occurrences that has both fish and rat inside 26 length | ||
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words.. I am bit comforted about the fact that I don't need to find lA and Cl nor lB and Cl.. | words.. I am bit comforted about the fact that I don't need to find lA and Cl nor lB and Cl.. | ||
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but not quiet.. anyone has any idea?? | but not quiet.. anyone has any idea?? | ||
--[[User:Kangw|Kangw]] 22:37, 27 January 2009 (UTC) | --[[User:Kangw|Kangw]] 22:37, 27 January 2009 (UTC) | ||
Revision as of 17:37, 27 January 2009
Ok does anyone know how to go about this problem?
I believe all you have to do for this problem is take the total number of ways to permute the 26 letters of the alphabet , which is 26!, and subtract all of the strings which contain the words 'fish', 'cat', and 'bird'. Namely if A='fish', B='cat', and C='bird' - |A or B or C| = |A| + |B| + |C| - |A and B| - |A and C| - |B and C| + |A and B and C|.--Spfeifer 19:06, 27 January 2009 (UTC)
However, if I understand the question correctly, each letter is only getting used once, so if 'i' is being used to make 'fish', it can't also be used to make bird. Same with 'r' for rat and bird. I'm i correct in thinking this? If so, using the notation from above, |A and C| and |B and C| should both be 0, correct?
Sounds like that is correct.. but I have no idea how to count the number of occurrences that has both fish and rat inside 26 length words.. I am bit comforted about the fact that I don't need to find lA and Cl nor lB and Cl.. but not quiet.. anyone has any idea?? --Kangw 22:37, 27 January 2009 (UTC)
