The answer is 5. (8/160=0.05)x 100= 5.
To figure this out you put part/whole=%/100 then cross multiply. 8/160=x/100 (put this in a square with 4 sections, like 2 fractions)...8x100=160x...800=160x... Then divide both sides by 160. That will put your x on one side and the percent you are looking for on the other.