# If 18 is 45% of a value, what is that value?

Mar 15, 2018


\text{18 is 45% of 40}


#### Explanation:



Consider the statement " x percent of y is z."

If any two of the variables are given, you can use algebra to find out the missing one. This results in three different kinds of problems. In each one, the unknown is in a different position.



• Problems where x is the unknown
(e.g. " What percent of 44 is 11? ")
• Problems where y is the unknown
(e.g. " 58 is 25% of what number? ")
• Problems where z is the unknown
(e.g. " What is 88% of 5000? ")



The word "of" in a word problem means multiply and the word "is" means equals.



45%\ \ of\ \ y\ \ is\ 18

Translate the problem into an algebraic equation:

$\frac{45}{100} \setminus \times y \setminus = \setminus 18$

$y \setminus = \setminus \frac{1800}{45}$

$y = 40$



That's it!