Answer:
B. f(n) = 56(0.5)^n-1
Step-by-step explanation:
First, You have to find out the starting population, if you look at the problem you see the population starts at 56
f(x) = 56
Second, you know that the population goes down 50% each week so it has a decay of 0.5
f(x) = 56(0.5)
Third, you need to add the exponent of n to make it exponential. But, if you just add n then the the population would be 28 on week 1 which is incorrect. To fix that you make the exponent n-1 so when you are on week 1 it doesn't become 28 but it stays on 56, and on week 2 it's 28, ect
f(x) = 56(0.5)^n-1
