The half life of a radioactive element is 8-days. How long it take to reduce it from 10 mg to 5 mg?

(A) 4 days (X)
(B) 12 days (X)
(C) 16 days (X)
(D) 8 days ()
(E) None of these (X)

Answers: The half life of a radioactive element is 8-days. How long it take to reduce it from 10 mg to 5 mg 8 days.