21 is what percent of 286 - 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 286 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 286, so we can write it down as 100%=286.
4. We know, that x% equals 21 of the output value, so we can write it down as x%=21.
5. Now we have two simple equations:
1) 100%=286
2) x%=21
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%=286/21
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 21 is what percent of 286

100%/x%=286/21
(100/x)*x=(286/21)*x       - we multiply both sides of the equation by x
100=13.619047619048*x       - we divide both sides of the equation by (13.619047619048) to get x
100/13.619047619048=x
7.3426573426573=x
x=7.3426573426573

now we have:
21 is 7.3426573426573% of 286