Twenty metal blocks are of the same size and external appearance; some are
aluminum, and the rest are
duraluminum, which is heavier.
Using a pan balance to determine how many blocks are aluminum, what is the minimum number of weighings to be done?
(In reply to
re(4): between... by Tristan)
Well, then, find it :)
My best is eleven, which meets your queue comment requirement.
I can't really see a way to determine how many ~and~ which ones are
duraluminum without using the full 19 weighings. Of course, the
expected number is much less based on a particular strategy, but
without knowledge of how many of each block there are, I can't lower
the worst case scenario.
re(5): between...
