21 is what percent of 2991 - 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 2991 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 2991, so we can write it down as 100%=2991.
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%=2991
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%=2991/21
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 2991

100%/x%=2991/21
(100/x)*x=(2991/21)*x       - we multiply both sides of the equation by x
100=142.42857142857*x       - we divide both sides of the equation by (142.42857142857) to get x
100/142.42857142857=x
0.70210631895687=x
x=0.70210631895687

now we have:
21 is 0.70210631895687% of 2991