rate of blowing balloons of Alexa = 15/20 = 0.75
rate of blowing balloons of Sara = 18/25 = 0.72
rate of blowing balloons of Shirley= 16/21 = 0.76
rate of blowing balloons of Sam = 12/23 = 0.52
from above calculation we concluded Shirley can blow balloons at the fastest rate!