SOLUTION: A poll of 500 people determines that 382 like ice cream and 362 like cake. How many people like both if each of them likes at least one of the two?

As the first approximation, add the two numbers 382 and 362:


    382 + 362 = 744.    (1)


But doing so, you count twice those people of 500, who like both products.


Therefore, your sum exceeds 500, although it should be equal 500, in reality.


This exceeding amount over 500 is exactly the number of those who like both products


    382 + 362 - 500 = 244.


It is your answer: 244 people like both products.