A sample of phosphorus-32 has a half-life of 14.28 days.
If 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample?
:
Using the radioactive decay formula: A = Ao*2^(-t/h), where
A = resulting amt after t time
Ao = initial amt (t=0)
t = time
h = half-life of substance