The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 125 grams of a radioactive isotope, how much will be left after 5 half-lives? Use the calculator provided and round your answer to the nearest gram.
so, 0.5^5 is 0.03125 multiply that by 125 and get your answer. *3.90625* (4) just saying, I got the 0.5^5 thing because 5 is the number of half-lives (x) and 0.5 is the rate of loss (or whatever its called). If it were to gain, you would put 1.5
