Let Grace be x
Nicole: 4x
Sara: 8x
Since all the girls added together equals 52 peppermints, you can form the equation: x + 4x + 8x = 52. Once simplified (combine like terms) you get 13x=52. Finally, you divide 52 by 13 to get the final answer x=4.
4x4=16, Nicole has 16 peppermints.