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
between... by Charlie)
Just a note on your initial assumptions. Based on the one Logic course I took 10 years ago...
Logically, Some = at least one, as many as all. (Some poeple are born, Some candies are chocolate, some people are identical to me in every respect. All these are true)
All = at least zero, but none that do not qualify (All moons made of cheese are invisible, all counting numebrs are integers. All these are true)
Now, when we take the remainder of a "some", what do we know? I'm not sure that we do know that there is at least one duraluminum block. Not of course that this changes anything...