Problem 4 [10 points] The normal respiratory rate of an adult is roughly 12 to 20 breaths per minute. This means that an average adult will complete a breathing circle of inhaling and exhaling ap- proximately every 4 seconds. Our lungs can store a maximum of 6,000 mL of air when we take a full, deep breath and a minimum of 5,500 mL after an exhale. If at time t = 0 you have just exhaled then: (A) Write a function that models the amount of air in your lungs.