3.99 is what percent of 4.2 - 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 4.2 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 100% equals 4.2, so we can write it down as 100%=4.2.
4. We know, that x% equals 3.99 of the output value, so we can write it down as x%=3.99.
5. Now we have two simple equations:
1) 100%=4.2
2) x%=3.99
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:
100%/x%=4.2/3.99
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 3.99 is what percent of 4.2

100%/x%=4.2/3.99
(100/x)*x=(4.2/3.99)*x       - we multiply both sides of the equation by x
100=1.0526315789474*x       - we divide both sides of the equation by (1.0526315789474) to get x
100/1.0526315789474=x
95=x
x=95

now we have:
3.99 is 95% of 4.2