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Six hundred coins (Posted on 2006-12-22) Difficulty: 2 of 5
I created six hundred coins. I tell you that each is red on one side, but may be red or blue on the other side. I flip each coin, and show you the resulting colors. You count 400 red and 200 blue. What is your best estimate of the number of coins that are red on both sides?

I flipped all the same coins again, and you count 350 red and 250 blue. How should you modify your estimate?

See The Solution Submitted by Tristan    
Rating: 4.5000 (2 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
No subject 2John zadeh2007-06-25 22:30:54
No SubjectJohn zadeh2007-06-25 22:29:04
Good One!!alex2007-04-11 10:57:41
coinsDave2006-12-24 06:33:59
For question 1...Caz2006-12-23 02:46:10
re: WrongJoel2006-12-23 01:13:04
Hints/TipsWrongTristan2006-12-22 21:23:11
re(2): I might think you cheated.Jer2006-12-22 15:03:08
Some Thoughtsre: I might think you cheated.Federico Kereki2006-12-22 14:13:46
SolutionI might think you cheated.Jer2006-12-22 11:42:40
Some ThoughtsNot so fastSteve Herman2006-12-22 09:59:11
SolutionAnswersOld Original Oskar!2006-12-22 08:53:33
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