Maths Puzzle

This once drove my grandad and I to distraction, we even got scales and marbles out on the kitchen table.

Can you solve it without seeing the solution below?

The Puzzle: You have 9 balls, equally big, equally heavy - except for one, which is a little heavier.

How would you identify the heavier ball if you could use a pair of balance scales only twice?

. . . . . . (Scroll down if you really want to see the Solution ...) . . . . . . . . . . . . . . . . . . . . The Solution . . .

Divide the 9 balls into 3 groups of 3. Compare the weight of two of those groups.

The heavier group should then be obvious, it will either tip the scales, or, if the scales stay balanced, then it is the group you didn`t include.

Now, choose 2 balls from this group and compare their weights, and using the same logic as before, the heavier ball will be obvious.

Obvious now?

The point . . .

So now you know the method of solving balance problems like this, they`re not hard anymore...what if there were 8 balls one was heavier, and you could use the scales twice?

Maths is a language, if you learn and understand the terms and techniques then exams are just showing you can apply your knowledge.