What is 99.9 percent of 400000000 - 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 400000000 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 400000000 is 100%, so we can write it down as 400000000=100%.
4. We know, that x is 99.9% of the output value, so we can write it down as x=99.9%.
5. Now we have two simple equations:
1) 400000000=100%
2) x=99.9%
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:
400000000/x=100%/99.9%
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 99.9% of 400000000

400000000/x=100/99.9
(400000000/x)*x=(100/99.9)*x       - we multiply both sides of the equation by x
400000000=1.001001001001*x       - we divide both sides of the equation by (1.001001001001) to get x
400000000/1.001001001001=x
399600000=x
x=399600000

now we have:
99.9% of 400000000=399600000