What is 3 percent of 128.9 - 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 128.9 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 128.9 is 100%, so we can write it down as 128.9=100%.
4. We know, that x is 3% of the output value, so we can write it down as x=3%.
5. Now we have two simple equations:
1) 128.9=100%
2) x=3%
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:
128.9/x=100%/3%
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 3% of 128.9

128.9/x=100/3
(128.9/x)*x=(100/3)*x       - we multiply both sides of the equation by x
128.9=33.333333333333*x       - we divide both sides of the equation by (33.333333333333) to get x
128.9/33.333333333333=x
3.867=x
x=3.867

now we have:
3% of 128.9=3.867