Question 21
I have five coloured discs in a pile as shown.
I take the top two discs and put them on the bottom (with the red disc still on top of the blue disc).
Then I again take the top two discs and put them on the bottom.
If I do this until I have made a total of 21 moves, which disc will be on the bottom?
I take the top two discs and put them on the bottom (with the red disc still on top of the blue disc).
Then I again take the top two discs and put them on the bottom.
If I do this until I have made a total of 21 moves, which disc will be on the bottom?