When a gnome dies, he decays radioactively. A cat wanders into my garden and kills a gnome, but in true cat fashion just killed it for fun...never intending to eat it. The gnome is left to decay. The half-life of a gnome is 15 days. The dead gnome originally weighed 22 pounds.
a. How much of gnome is remaining after 3 weeks?
b. When will there be only 5 pounds of gnome remaining