3 Hats and 2 Guesses

There are 100 persons attending a party during which on top of the heads of each person a hat is place which may be either red, blue, or green. However no one can see the colour of his/her own hat but can see the colour of others' hats. Everyone is given a choice of 2 chances to guess the colour of thier own (with the 3 colours) hat but they need not utter it consecutively. They may exercise the first chance now and after some time they may do so for the second chance. They may be permitted together to evolve a strategy to achieve this possible. Under no circumstances, should a person utter other than the colour of the hats in two chances and no more extraneous talks. How to find the winning strategy so that every person finds correctly the colour of his/her own hat in the 2 chances?

Answer:

All the persons should sit in a form of a circle and let them be labelled 1,2,3, ......................upto 100 in a clock-wise direction. Now 1 starts by exercising his first option mentioning 2nd's colour, 2nd person saying the 3rd's colour and so on and so forth until 100 says 1'st person's hat colour and since by that time everybody knows their own colour starts the second chance by uttering the colour of their own hats since they knew it by now.