91 is what percent of 643 - 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 643 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 643, so we can write it down as 100%=643.
4. We know, that x% equals 91 of the output value, so we can write it down as x%=91.
5. Now we have two simple equations:
1) 100%=643
2) x%=91
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%=643/91
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 91 is what percent of 643

100%/x%=643/91
(100/x)*x=(643/91)*x       - we multiply both sides of the equation by x
100=7.0659340659341*x       - we divide both sides of the equation by (7.0659340659341) to get x
100/7.0659340659341=x
14.152410575428=x
x=14.152410575428

now we have:
91 is 14.152410575428% of 643