PLEASE HELP I AM FAILING! Organisms A and B start out with the same population size.

Organism A's population doubles every day. After 5 days, the population stops growing and a virus cuts it in half every day for 3 days.

Organism B's population grows at the same rate but is not infected with the virus. After 8 days, how much larger is organism B's population than organism A's population? Answer the questions to find out.

By combining the increase and decrease, find an exponential expression for the total change in organism A's population after 8 days. Show your work.