Logic with weights
Balance Scale
Every scale shown is perfectly balanced. Use them to work out how many of one shape would balance a new load.
How to play
- Look at the balanced scales. Each side of a scale weighs the same.
- Answer how many of the named shape would balance the load on the last scale.
- After each answer you see a set of weights that fits every scale and how the answer follows.
What it trains
Deductive reasoning and the first steps of algebra: replacing one thing with something of equal value until the problem becomes simple.
Like any brain game, it makes you better at this kind of puzzle. There is little evidence that games like this raise IQ itself, so treat it as practice and fun.
Learn the trick
Swap, do not calculate. If one square balances two circles, you can replace every square with two circles anywhere. Keep swapping until only one kind of shape is left on both sides.
Start from the simplest scale. A scale with one shape on one side tells you the most. Use it first.
Give the lightest shape a weight of 1. Then work out the others from it. Only the ratios matter, so any starting number gives the same answer.
Remove the same thing from both sides. If a circle sits on both sides of a scale, you can take it off both and the scale stays balanced.