Let $ Q $ represent a mass of radioactive plutonium $ \left(^{239}Pu\right) $ (in grams), whose half-life is $ 24,100 $ years. The quantity of plutonium present after years is $ Q = 16 \left(\dfrac{1}{2}\right)^{t/24,100} $
(a) Determine the initial quantity (when $ t = 0 $).
(b) Determine the quantity present after $ 75,000 $ years.
(c) Use a graphing utility to graph the function over the interval $ t = 0 $ to $ t = 150,000 $.