A simple to state, but tricky to work out maths and logic puzzle this week.
You have a metal ingot that weighs 40 kilograms. How can you recast the ingot into four new ingots that allow you to weigh any weight between one kilogram and 40 kilograms inclusive?
The four ingots must weigh 1, 3, 9 and 27 kilograms.
One kilo can be weighed with the 1 kilo weight.
Two kilos can be weighed with the 1 kilo weight on one side of the balance and the 3 kilo weight on the other side.
And so on.