Answer: 1% is your answer
It's (1/100) * 100 or 1% is the percentage strength of a 1:100 solution.
Explanation:
l NOTE:
l To change ratio strength to percent strength, it is
sometimes convenient to "convert" the last two zeros in
a ratio strength to a percent sign (%),
l change the remaining ratio to a common fraction, and
then to a decimal fraction in expressing percent.
l Examples:
l 1:100 =1/1% = 1%
l 1:200 = ½% = 0.5%
l 3:500 = 3/5% = 0.6%
l 1:2500 = l/25% = 0.04%
l 1:10,000 = 1/100% = 0.01%