Question

A chemist begins with 120 mL of a radioactive substance that decays exponentially. After 24 hours, only 30 mL of the substance remain. How many mL will remain after 48 hours? 12.5 mL 7.5 mL 4.5 mL 9.5 mL

Answer 1

7.5 mL

Explanation:

If it decays exponentially then you divide the previous number by 4 to get the next number and 30 divided by 4 is 7.5mL.