Answer:
when both parents have brown eyes, you have a 19% chance of getting blue eyes. (referenced in the picture below).
it is kinda a confusing concept, but this means that the parents either have 2 blue genes and 2 brown genes in the eye, and when there is 2 recessive genes in the eye it will cover the dominant gene.
dominant genes are the capital letter, and recessive genes are the lowercase (ex. Gb)