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T _ G _ T H _ R Clue
THE SON HAD SHOWED HIS FATHER A MATCH. WHENEVER HE LIT THE MATCH, IT FILLED THE ENTIRE ROOM WITH LIGHT, YET IT WAS STILL SMALL ENOUGH TO FIT INTO HIS POCKET THE MINIMUM NUMBER OF WEIGHTS REQUIRED IS FIVE AND THESE SHOULD WEIGHT 1, 3, 9, 27 AND 81 POUNDS. THE MERCHANT HAS TO USE A BALANCE WEIGHING SCALE TO DO THE JOB. TO WEIGH 2 POUNDS, HE'LL HAVE TO PUT THE 3 POUND WEIGHT ON ONE PAN AND 1 POUND WEIGHT ON THE OTHER PAN. TO WEIGH 5 POUNDS, HE'LL HAVE TO PUT THE 9 POUND WEIGHT ON ONE PAN AND 1 AND 3 POUND WEIGHTS ON THE OTHER PAN TAKE THE FOX OVER, RETURN WITH NOTHING. GO OVER WITH ONE CHICKEN, RETURN WITH THE FOX. GO OVER WITH THE SECOND CHICKEN, RETURN WITH NOTHING. FINALLY, TAKE THE FOX OVER. OR LET: MAN = M FOX = F CHICKEN1 = C1 CHICKEN2 = C2 THIS IS HOW THEY CROSS THE RIVER: M,F → ← M M,C1 → ← M,F M,C2 → ← M M,F → FIRST THE TWO SONS ROWED ACROSS THE RIVER AND ONE STAYED BEHIND WHILE THE OTHER RETURNED IN THE BOAT TO HIS FATHER. THE SON REMAINED BEHIND WHILE THE FATHER CROSSED THE RIVER. THEN THE OTHER SON BROUGHT BACK THE BOAT AND THE TWO BROTHERS ROWED OVER TOGETHER