Question

Compound Interest Problem?
An endangered species of fish has a population that is decreasing exponentially. The populations 5 years ago was 1900. Today, only 1100 fish are alive. Once the population drops to 100, the situation will be irreversible. When will this happen?

Answer 1

let its rate constant be r.
\[1900*e^{-5r}=1100\]
\[r=0.1093\]
let the time be t.
\[1100*e^{-0.1093t}=100\]
\[t=21.93\approx22\]

Answer 2

add back the units by yourself :)

Answer 3

@desiretoinspirecindy

Answer 4

Sorry, I had went off my computer .. but THANKS! I got that answer eventually, I was a little confused, but now you just confirmed it was right! THANKS!!

Answer 5

no problem :)
(i was sleeping lolz)