DECEMBER CHALLENGE Bittersweet Beer
Brainteaser : You have 1,000 bottles of beer . One contains poison and tastes bitter . How do you find the poisoned bottle using the smallest number of sips ?
Please send you answers to Thomas Selling via e-mail : thomasselling @ me . com Correct responses will be recognized in the future issues of the New Hampshire Civil Engineer .
NOVEMBER SOLUTION
You will need to start moving up the building in increments of floors for the first bulb . This could be 10 floors at a time , say . Once you find the point where the first bulb breaks , start again in smaller increments from the last previous incremental floor . So , say you went up in 10-floor increments and it breaks at floor 20 , move back to floor ten with the second bulb . Then start dropping it in 1-floor increments . This will give you a worst case of 19 . But we can improve on this . Say you tried floor 16 first . Let ' s say it breaks . Go back to floor one and move up in one-floor increments ( floors 1-15 ). This will give you a worst case of 16 drops , if floor 16 was the breaking point , for the second bulb , in the worst case . You can , of course , extend this principle if it doesn ' t break at floor 16 . You could move to floor 31 , 45 , 58 etc . for the first bulb etc . Given the use of the same method , you ' ll always reach a worst case of 16 drops to find the floor .
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