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Donald Cartmill

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About Donald Cartmill

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  1. Protecting Airplanes

    Actually I think this goes back a long way to the old Saturday evening post. The military had made a study of all of the planes that had made it back from air raids. Cataloged every bullet hole that had pierced the hull of these airplanes . There were suggestions that these areas should be armor plated . Someone else spoke up making the statement, that in fact these were the planes that made it back meaning these areas were less damaging to the plane ability to fly ,and the armor plating could best be used else where
  2. Balancing Gold Coins

    The number is 3 coins
  3. I bake

    I am with gavinksong...there is only one answer which is the lowest common denominator for the three groups (plus 1)
  4. Balancing Gold Coins

    The maximum number of coins for the solution is 3. This is basically what you arrive at when deriving the odd coin in a group of 12 ,allowing only 3 weighings, the maximum number for a solution is 3. Bottom line is that step 1) taking 1/3 of the coins on each pan and leaving 1/3 off. If they balance then step 2) divide those previously left off again into 1/3 on each pan and 1/3 off. 3) You will continue this until you are down to 3 coins. Then 1 on each pan , if they balance then the one left off is the odd coin. A) Now if at any time the number of coins is not evenly divisible by 3 ,then the left over coins go in the pile left off. B) If at any time during the early stages the pans do not balance , you will remove the right pan coins and divide the left pan into half placing 1/2 on each pan...they balance ,then the odd is obviously in the group removed from the right pan and start again at step 2) Now if they do not balance repeat B)
  5. Mouse & Cheese Cube

    I get 24 cubes ; 7 in the front face ; 9 in the middle ; and 8 in the rear face
  6. More heads?

    50% chance of more heads by (A) ; " X " equal number of coins by (A) and (B) are 50/50 , Therefore the results of a single coin toss is the answer ,which is 50%.