Alright so i have exams in a matter of days and stumbled upon this multiple choice question
7. A radioactive source has 1.6×10^20 atoms of a radioactive isotope, with a half-life of 3 days. How many atoms will decay in 12 days?
A. 1.0×10^19
B. 1.2×10^20
C. 4.0×10^19
D. 1.5×10^20
So my first...