Question

Plutonium-240 decays according to the function Q(t)=Q(subscripto)e^(-kt) where Q represents the quantity remaining after t years and k is the decay constant, 0.00011... How long will it take 27 grams of plutonium-240 to decay to 9 grams?
A.) 1.44 years
B.) 18,900 years
C.) 9,990 years
D.) 2,100 years