If we start at 100,000 and double every three hours until 6 hours, to colony will be at 400,000 bacteria.
First find out how many times it will double by dividing 6/3=2. It will double twice in 6 hours. Next double 100,000 once, to get 200,000. Then, double it once more to get to the final answer of 400,000 bacteria.
