Calculus II Exponential Growth and Decay

Question

The half life of substance A is 19 years, and substance B decays at a rate of 30% each decade.

(a) Find a formula for a function f(t) that gives the amount of substance A, in milligrams, left after t years, given that the initial quantity was 100 milligrams.

(b) Find a formula for a function g(t) that gives the amount of substance B, in milligrams, left after t years, given that the initial quantity was 100 milligrams.

Answer 1

f(t) = 100(0.5)^t/19

g(t) = 100(0.7)^t/10

Answer 2

19/10=1.9

(t/10).30

100-B/t