Hi Mark,

>Let's say on day one, I see 2 green hats and 97 red hats. One of the Green hats sees 97 red, the other Green hat plus mine. On day 2, all 100 are back. If my hat is red, each of the 2 green smurfs now know their own hat is green because on day 1 the green hats saw 98 red and 1 green. If my hat is green, they will not know their color until tomorrow.

Hmmm... Let's say I see 2 green hats, and 97 red hats. All other green smurfs see the same, while all red smurfs see 96 red hats and 3 green hats. How should I know which color my hat has (supposing there are no mirrors)?

Only if there's only one green hat, that smurf knows what color his hat has. When there's more than one, his could be either red or green. This is true for both green smurfs.

Christof