Unformatted text preview: k using at most 15 drops. Prove that your answer always works. Fine print: All of Weston’s watermelons behave exactly the same. When dropped from the same ﬂoor, they always break or always survive. If a watermelon breaks, it cannot be used again. If a watermelon survives a fall, it is totally unaﬀected by the fall. Extra Credit: Prove that it is not possible to always determine the answer with less than 15 drops. 4. You are given twelve gold coins and a balance. The coins look and feel identical to you. However, you know that one of them weighs a slightly diﬀerent amount. The other eleven are all the same weight. Using the balance at most three times, determine which coin is diﬀerent. (As a warm-up, try ﬁnding a bad coin among four in two weighings.)...
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This note was uploaded on 03/14/2012 for the course MATH 55 taught by Professor Strain during the Summer '08 term at Berkeley.
- Summer '08