In an appropriate environment, guppies reproduce at an astounding rate. A population of breeding guppies quadruples every month. How many guppies will there be after 9 months if the beginning population is only 6 guppies?

After 9 months, the population of guppies will be (6 guppies) * (4^9) = 6 * 262144 = 1,572,864 guppies.