During normal breathing, about 12% of the air in the lungs is replaced after one breath. Write an exponential decay model for the amount of the original air left in the lungs if the initial amount of air in the lungs is 500 mL. How much of the original air is present after 240 breaths?

Answer 1

after n breaths, the amount left is

500*.88^n

Answer 2

500(0.88)^n

Answer 3

2.370