A petri dish starts off with 10 bacteria, and the bacteria population doubles every hour. How many bacteria are in the petri dish after 8 hours?

bacteria

*y* = a b* ^{x }*a: start value, b: multiplier.

We first write an exponential model for this situation, then plug in

a = 10, b = 2, *x* = 8

*y* = 10 × 2^{x}

*y* = 10 × 2^{8}

*y* = 10 × 256

*y* = 2560 bacteria