**When expressed as a fraction, 15 percent is equal to 15/100.** This can be simplified further by dividing both the numerator and denominator by 5, resulting in 3/20.

The word percent means per hundred, and percentages can be seen as an expression of regular numbers or ratios as a fraction of 100. In order to convert percentages back to fractions, one simply needs to see the percentage as a number over 100, and then find the greatest common factor between the two of them. After this, the percentage and 100 are both divided by the greatest common factor to find the simplest fraction that represents the original percentage.