Ok so first of all it's in percent. You can turn that into a fraction easily because percent is based on a total of 100.
Now since 8.6 has a decimal unit you might want to turn it into fraction.
8.6= 8+6/10 = 80/10+6/10
Now you sum them.
86/10
Now since 86/10=8.6 and that 8.6 was out of 100 then you can do a composed fraction.
86/10 * 1/100
Do the operation and you get
86/1000
Now to reduce the fraction try to divide both numbers between the smallest prime numbers (2,3) till you can't do it anymore. (it has to be the same number used for both)
dividing by 3 will get you a number with decimals and by 2 it gets your fraction reduced to 43/500