You can
put this solution on YOUR website! .
Since 40% of the item's cost is $240, it means that 10% of the item's cost is 240/4 = 60 dollars.
Hence, the item's full cost is 10 times $60, or $600. ANSWER
It is how to solve the problem MENTALLY for a 5-th grade student
(or for a 75-years old person) without using equations.