What is 4.0E-5 percent of 21000000 - 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 21000000 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 21000000 is 100%, so we can write it down as 21000000=100%.
4. We know, that x is 4.0E-5% of the output value, so we can write it down as x=4.0E-5%.
5. Now we have two simple equations:
1) 21000000=100%
2) x=4.0E-5%
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:
21000000/x=100%/4.0E-5%
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 4.0E-5% of 21000000

21000000/x=100/4.0E-5
(21000000/x)*x=(100/4.0E-5)*x       - we multiply both sides of the equation by x
21000000=2500000*x       - we divide both sides of the equation by (2500000) to get x
21000000/2500000=x
8.4=x
x=8.4

now we have:
4.0E-5% of 21000000=8.4