Question

If 30 is 20 percent of a number, then the number is what percent of 30?

Answer 1

percent means parts out of 100 so 20% means 20/100

short version, longer version below
20%=1/5
30=1/5
5/5 is 5 times of 1/5
500%=5 times
number is 500% of 30

longer explanation

30=20/100 of a number
30=2/10 of a number
30=1/5 of a number
multiply both sides by 5
150=5/5 of a number
30=1/5 of 150
100% means 1 times
200% =2 times
500%=5 times
150 is 500% of 30