A distant planet is inhabited by creatures having more than two arms. The ones with an even number of arms are the knights who always tell the truth; the ones with an odd number of arms are the liars who always speak falsely.

The rules of the planet allow only creatures having eight, nine or ten arms to work as guards. Four guards are conversing amongst themselves:

• The blue one says, "All together we have 36 arms."
• The cyan one says, " All together we have 35 arms."
• The brown one says, "All together we have 34 arms."
• The beige one says, "All together we have 33 arms."

Determine the number of arms of each guard.

only one can be telling the truth .

one even and 3 odd  ->8+3*9=35 forces one answer :

only cyan is a knight

Posted by Ady TZIDON on 2013-01-10 13:49:04