There are 6 coins weighing 1, 2, 3, 4, 5 and 6 grams that look the same, except for their labels. The labels are supposed to display the weights of the coins.
How can you determine whether all the labels are correct,
using the balance scale only twice?
(In reply to
Solution by Brian Smith)
When weighing labels
126 vs 45 expecting 9 on each side
235 vs 46 expecting 10 on each side
In weighing those labeled 123456 in that order, and the actual weights, in order are:
123456: then of course this is correct with 9 and 10 totals.
135624: this weighs 8 on each side and 10 on each side, though mislabeled.
321465: 10 on each side then 9 on each side, though mislabeled.
531642: 10 on each side then 8 on each side, though mislabeled.
So 3 possible ways of mislabeling get through this test.

Posted by Charlie
on 20160113 12:40:10 