This problem can be represented through the following equation
A = A₀(1/2)^t/h where A-----------> is the amount of substance left after time t A₀ ----------> is the original amount---------> 2 g h-------------> is the half-life-----------> 8 days
for A=0.04 g t=? 0.04 = 2(1/2)^t/8 0.02 = (1/2)^t/8 Take ln on both sides: ln(0.02) = ln [(1/2)^t/8] ln(0.02) = (t/8)(ln 1/2) t = 8*ln(0.02)/ln(1/2) t = 45.15 days
