Solving equations with light. (Courtesy: iStockphoto/Henrik Jonsson) 3x + y = 2. x + 3y = 0. It’s the sort of easy maths problem that you can work out in a few minutes using pencil and paper, but ...

Here are 10 math problems that confused people across the internet. Can you solve them?

Plug your answer back into the original equation to make sure both sides are equal. This simple step helps catch small mistakes, like forgetting a negative sign or making a calculation slip.