After a special medicine is introduced into a petri dish containing a bacterial culture, the number of bacteria
1
remaining in the dish decreases rapidly. The number of bacteria decays by a factor of every
6.7
15
minutes, and can be modeled by a function, N, which depends on the amount of time, t (in minutes).
Before the medicine was introduced, there were 90,000 bacteria in the Petri dish.
Write a function that models the number of bacteria t minutes since the medicine was introduced.