A box of candies can be equally divided by weight without cutting pieces
between three, four or seven people.
Each piece is an integral number of ounces.
What is the least number of pieces of
candy the box could contain? The candies may be of different weights.
(In reply to re: Solution
If there existed a 9-pieces solution, we could imagine a zero ounces piece, and then we'd have a 10-pieces solution. Since it was proved there is no 10-pieces solution whatsoever (with or without zero weight pieces) then it follows there isn't a 9-pieces solution either.