A sample of radioactive material has a half life of 35 days. what is the fraction of the original quantity that remains after 105 days

105/35 = 3

Explanation:

This means that say the radioactivity was 100 then that would half 3 times. 100-50, 50-25, 25-12.5.

Extra information:

No matter what the half life is this number will never reach zero as it will continue to half, however it will become to small to eventually read