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Six glasses
Riddle statement
Six identical glasses are lined up on a table.
The first three are full of water and the last three are empty:
full, full, full, empty, empty, empty
You can only move one glass, and do it only once.
How do you leave them alternating full, empty, full, empty, full, empty?
Show solution
Solution
The initial arrangement is:
L, L, L, V, V, V
If you take the second glass - which is full - and pour its contents into the fifth - which is empty -, the arrangement is:
L, V, L, V, L, V
They alternate perfectly. You have only moved one glass, and only once.