A bacterial population quadruples every hour. After five hours, there are 3072 bacteria in a petri dish.
How many bacteria were initially in the petri dish?
after 5 hours there were 3072
after 4 hours there were 768
after 2 hours there were 192
after 1 hour there were 48
initially there were 12
or
a(4^4) = 3072
a(256) = 3072
a = 3072/256 = 12