Answer: After each half-life, the amount of radioactive isotope will be reduced to half its previous amount. Therefore, after 5 half-lives, the amount remaining will be:
155 grams / 2^5 = 4.84 grams (rounded to two decimal places)
So, after 5 half-lives, approximately 4.84 grams of the radioactive isotope will be left.
Explanation: