Abstract
You cannot see what is written on your own forehead. But you can see what is on the forehead of the person who you are talking to. In the original version of the riddle you only know your own number, but not the other’s number. In this version you only know the other’s number, but not your own number. Otherwise, there is no difference. After the announcements the remaining number pairs are now \((2,1)\) and \((3,2)\), not \((1,2)\) and \((2,3)\).
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© 2015 Springer International Publishing Switzerland
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van Ditmarsch, H., Kooi, B. (2015). Answers. In: One Hundred Prisoners and a Light Bulb. Copernicus, Cham. https://doi.org/10.1007/978-3-319-16694-0_13
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DOI: https://doi.org/10.1007/978-3-319-16694-0_13
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Publisher Name: Copernicus, Cham
Print ISBN: 978-3-319-16693-3
Online ISBN: 978-3-319-16694-0
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