Half life question?

Question

The isotope 228-Ra has a half life of 1602 years. How long would it take a sample of this isotope to decay to just 70.63% of its original activity? Answer in years Error tolerance: ±1%


A radioactive isotope has an initial decay rate of 43.71 dps (disintegrations per second) for a sample. After an elapsed time of 55.81 days, the rate has decreased to 17.78 dps. What is the half-life (in days) of this isotope? Error tolerance: ±1%

Answer 1

803.81 yrs

43 days