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(2): between...
It seems we (starting with me) have been misinterpreting the problem. We don't need to identify which blocks are which--only determine how many of the twenty are duraluminum. That's only 20 possibilities. I doubt that it's possible in three weighings (which have 27 possible outcomes).
Posted by Charlie
on 2005-06-05 22:31:36