5. Selenium-83 has a half-life of 25.0 minutes. How many minutes would it take for a 10.0
mg sample to decay and have only 1.25 mg of it remain?


Answer :

Explanation:

10.0mg / 1.25mg = 8

1/8 of the original mass => 3 half-life phases

Hence it will take 25.0 min * 3 = 75.0min.