What is 39.9 percent of 9.99 - step by step solution

To get the solution, we are looking for, we need to point out what we know.

1. We assume, that the number 9.99 is 100% - because it's the output value of the task.
2. We assume, that x is the value we are looking for.
3. If 9.99 is 100%, so we can write it down as 9.99=100%.
4. We know, that x is 39.9% of the output value, so we can write it down as x=39.9%.
5. Now we have two simple equations:
1) 9.99=100%
2) x=39.9%
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
9.99/x=100%/39.9%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 39.9% of 9.99

9.99/x=100/39.9
(9.99/x)*x=(100/39.9)*x       - we multiply both sides of the equation by x
9.99=2.5062656641604*x       - we divide both sides of the equation by (2.5062656641604) to get x
9.99/2.5062656641604=x
3.98601=x
x=3.98601

now we have:
39.9% of 9.99=3.98601