Have you figured it out yet?
Take another careful look before jumping to an answer.
At first glance, this puzzle looks very simple.
Most people immediately focus on the number 90.
That is exactly where many mistakes begin.
Start with the small balance on the right.
It is perfectly level, which means both sides have the same total weight.
On the left side of the small balance, there are three pink balls.
On the right side, there is a weight labeled 90.
Since the balance is even, the three pink balls together must weigh 90.
Now divide that total equally.
Each pink ball weighs 30.
So far, the puzzle is easy.
Now move your attention to the large balance.
The left pan holds two white balls and one pink ball.
Since one pink ball weighs 30, the total weight on the left side is two white balls plus 30.
Many people now make a common mistake.
They look at the small balance hanging on the right side and think it weighs only 90.
But that is not how a hanging balance works.
The large balance is not supporting only one side of the small balance.
It is supporting the entire small balance.
Everything hanging below the hook contributes to the total weight.
That includes both pans of the small balance.
The left pan contains three pink balls.
Their total weight is 90.
The right pan contains the weight labeled 90.
That side also weighs 90.
The small balance itself is balanced because both sides are equal.
When the entire balanced scale hangs from the large balance, the hook carries the combined weight of both sides.
So the total load hanging from the right side of the large balance is 90 plus 90.
That gives us 180.
Now compare both sides of the large balance.
The left side weighs two white balls plus one pink ball.
The right side weighs 180.
Since the large balance is level, both sides must be equal.
Write the equation.
Two white balls plus 30 equals 180.
Subtract 30 from both sides.
Two white balls equal 150.
Now divide by two.
Each white ball weighs 75.
That is the correct answer.
The white ball weighs 75.
This puzzle is a great reminder that careful observation is often more important than fast calculation.
The number 90 is not the final clue.
The real trick is understanding what the large balance is actually holding.
If you notice that the hook supports the entire small balance instead of just one side, the solution becomes clear.
Many people answer 30 or 45 because they forget that both sides of the hanging balance contribute to the total weight.
Once you avoid that mistake, the math is straightforward.
