Thread: exponential growth help

Rabbit populations are considered to grow exponentially. A farmer buys 8 rabbits and finds that within 6 months he now has 24 rabbits. How many more months must the farmer wait until he has 216 rabbits?

Find k. $\displaystyle 24=8e^{-k(6)}$

Solve for k, then use it in $\displaystyle 216=8e^{-kt}$ and solve for t.