Question

Which of the following are examples of exponential decay? select all that apply.

a) the population of Florida is increasing by 43% each year
b) the pesticide DDT has a half-life of 15 years
c)march madness has 64 teams in the bracket. each round, half of the teams are eliminated
d)after an antibiotic is added to a culture of bacteria, the number of bacteria is reduced by half every three hours
e) a tree frog population doubles every three weeks

Answer 1

B, C and D are exponential decay.

Half-lives are given by exponential function, and since they are decreasing, it is decay.
With the teams being eliminated, this is decay.
Bacteria can be represented by exponential functions, and it is decreasing.