Like this:
Percent. Numbers.
X% 0.13
----- = -------
100%. 65
So you use that to Cross multiply and do this:
X times 65 which is 65x
100 times 0.13 which is 13
So: 65x=13
You leave the ex alone and divide 13 by 65
X = 13
------
65
Your result would be
X= 0.2
