scooby_doo_do Posted March 18, 2005 Share Posted March 18, 2005 3 x Barrels 1 x Barrel with 100 x Black balls 1 x Barrel with 100 x White balls 1 x Barrel with 50 x Black balls 50 x White balls Each barrel has a label which could be "Black Balls Only", "White Balls Only", "Black or White Balls", but the barrels have the incorrect label. How many balls need to be extracted before you can identify the correct label for each barrel? Link to comment Share on other sites More sharing options...
Marco Posted March 18, 2005 Share Posted March 18, 2005 50? Link to comment Share on other sites More sharing options...
cashpoint Posted March 18, 2005 Share Posted March 18, 2005 51 Link to comment Share on other sites More sharing options...
scooby_doo_do Posted March 18, 2005 Author Share Posted March 18, 2005 Nope... Both wrong so far....... Link to comment Share on other sites More sharing options...
scooby_doo_do Posted March 18, 2005 Author Share Posted March 18, 2005 The answer is.... 1 Link to comment Share on other sites More sharing options...
Dragonball Posted March 18, 2005 Share Posted March 18, 2005 OK - I give in - why cant the single ball be from the barrel with 50/50? Or is it one of those trick jobbies? Link to comment Share on other sites More sharing options...
SimonB Posted March 18, 2005 Share Posted March 18, 2005 I've got it, it's because it says the barrels HAVE the incorrect label, not may have. So the one that says "black or white balls" must actually have either all white balls or all black in. So you take one ball from that barrel. If it's white the correct label for that barrel is "white balls". If it's black the label is "black balls". Then just swap the other two barrel labels round. Link to comment Share on other sites More sharing options...
scooby_doo_do Posted March 18, 2005 Author Share Posted March 18, 2005 Thats the one..... Glad i confused you all after your Friday lunchtime beer :-) Link to comment Share on other sites More sharing options...
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