The answer is quite simple, and can be displayed as a fraction of the outcome. The denominator would be 100, due to there being 100 attempts, and the numerator would be 47, because 47 were heads. Therefore, you get 47/100
In the function the .72 means that each unit of time 72% of the value is retained. This means that 28% percent of the value is lost or decays because 1-0.72=0.28 or 28 percent.
