Austin consumes an energy drink that contains caffeine. After consuming the energy drink, the amount of caffeine in Austin's body decreases exponentially. The 10-hour decay factor for the number of mg of caffeine in Austin's body is 0.2785.

a. What is the 5-hour growth/decay factor for the number of mg of caffeine in Zach's body?
b. What is the 1-hour growth/decay factor for the number of mg of caffeine in Zach's body?