Date: Jan 27, 1999 7:15 PM
I read your problem and have solved it straight away!
The key to the problem is being able to reduce the original number of
coins to 3...for obvious reasons.
I must warn you...I'm only fourteen so I may not be able to answer
what you really wanted.
However, I think one can determine the odd coin from 24 coins in four
Weighing 1 = determine heavier 12coins
2 = determine heavier 6coins
3 = determine heavier 3 coins
4 = determine heaviest coin
One cannot determine the odd coin from 38 in 4 weighings. This is
because by the end of the third weighing one is left with four coins.
In a single weighing one cannot find one heavier coin.
I hope you find this useful.