What is 2.1 percent of 400 - 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 400 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 400 is 100%, so we can write it down as 400=100%.
4. We know, that x is 2.1% of the output value, so we can write it down as x=2.1%.
5. Now we have two simple equations:
1) 400=100%
2) x=2.1%
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:
400/x=100%/2.1%
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 2.1% of 400

400/x=100/2.1
(400/x)*x=(100/2.1)*x       - we multiply both sides of the equation by x
400=47.619047619048*x       - we divide both sides of the equation by (47.619047619048) to get x
400/47.619047619048=x
8.4=x
x=8.4

now we have:
2.1% of 400=8.4