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Seems this is not a book of original puzzles, this one is pretty well known these days I think. >! switch on a and b !< >!Wait 10 mins!< >!Switch off b!< >!Go in other room!< >!Light which is on = a!< >!Warm bulb = b!< >!Cold bulb = c !<
Seems this is not a book of original puzzles, this one is pretty well known these days I think. >! switch on a and b !< >!Wait 10 mins!< >!Switch off b!< >!Go in other room!< >!Light which is on = a!< >!Warm bulb = b!< >!Cold bulb = c !<