tag:blogger.com,1999:blog-804641938070835983.post393052361523401546..comments2011-02-28T02:29:10.774-08:00Comments on The Big Beautiful Brain: Brain Teaser #002Dr. Brainhttp://www.blogger.com/profile/12448822254895770054noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-804641938070835983.post-54319200211145909392011-02-11T18:56:34.726-08:002011-02-11T18:56:34.726-08:00123456789
eeeeeoeee
weigh coins 1,2,3 and 4,5,6
w...123456789<br />eeeeeoeee<br /><br />weigh coins 1,2,3 and 4,5,6<br />weigh coins 1,5,7 and 2,6,8<br />weigh coins 3,4,8 and 1,6,9 on the other<br /><br />assuming each gold coin weighs 1 ounce.<br /><br />Scale one will be <br />3-2.9<br />scale 2 will be 2.9-3<br />and 3-3<br /><br />Scale 3 was even, so we know all the coins in that run were not the odd coin, which instantly eliminates 6. Which means it will be either coins 2,5 or 7. <br /><br />Knowing this we look back at tests 1 and 2. Test 1 shows us that Test 1, which included numbers 2 and 5, weighed 3-2.9, with the side containing coin 5 weighing slightly less and the side containing coin 5 weighed slightly more.<br /><br />In test 2 we see that when coins 5 and 7 are weighed together, they weigh slightly less then coin two coupled with 2 good coins. We can now deduct from this that coin 5 is the odd coin.<br /><br />Test 1 potentially bad coins 2 and 5 were weighed with two coins that were known to be good, we can now deduct that coin 7 is not the bad coin. With that we can look at test 2 and it is coin 2 and 5 once again each with 2 known good coins, this time we know that if coin 2 is heaview then coin 5, then coin 2 is the answer but since the side with coin 5 was lighter, as was with the first test, we know that it has the defect.<br /><br />I don't know if I did this right but I got the result I wanted. Hopefully I did but that was a mindbender, thanks!Ramsayhttps://www.blogger.com/profile/13102009474593659659noreply@blogger.com