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Test your logic

Posted on 10. Dec, 2009 by Jake in brain teasers

This week I’ve got logic puzzles that I think you may find interesting to solve. I only got 1 of the 2 correct but maybe you’ll manage to ace them all.

• Why is it better to have round manhole covers than square ones?
• You have an old-fashioned refrigerator with a small freezer compartment capable of holding seven ice cube trays stacked vertically. But there are no shelves to separate the trays, and if you stack one tray on top of another before the ice cubes in the bottom tray are fully frozen, the top tray will nestle into it, and you won’t get full cubes in the bottom tray. You have an unlimited supply of trays, each of which can make a dozen cubes. What’s the fastest way to make full-sized ice cubes?

Get the solutions next week.

Last week’s solutions:

Problem A: First fill the 5-litre bowl, overspill water from it to fill the 4-litre bowl, which you empty afterwards. Overspill the remaining 1 litre to the 4-litre bowl. Refill the 5-litre bowl and overspill water from it to fill the 4-litre bowl (where there is already 1 litre). Thus you are left with 2 litres in the 5-litre bowl.

Second, the same principle – this time from the other end. Fill the 3-litre bowl and overspill all of the water to the 4-litre bowl. Refill the 3-litre bowl and fill the 4-litre bowl to the top. And there you have 2 litres in the 3-litre bowl.

Problem B: Turn both sand-glasses. After 4 minutes turn upside down the 4-min sand-glass. When the 7-min sand-glass spills the last grain, turn the 7-min upside down. Then you have 1 minute in the 4-min sand-glass left and after spilling everything, in the 7-min sand-glass there will be 1 minute of sand down (already spilt). Turn the 7-min sand-glass upside down and let the 1 minute go back. And that’s it. 4 + 3 + 1 + 1 = 9

You can find more water and weighing puzzles at http://brainden.com/weighing-puzzles.htm

Tags: brain teasers, logic, puzzles