3. Below is a typical graph of the number N of bacteria grown in a batch culture as a function of time t. Describe what you think is happening during each of the four phases. N 0 t 4. A Boeing 747 crosses the Atlantic Ocean (3000 miles) with an airspeed of 500 miles per hour. The cost C (in dollars) per passenger is given by 36 000 C(92)=100+ 130+ '56 where :1: is the ground speed (airspeed :I: wind). (a) What is the cost per passenger for quiescent (no wind) conditions? (b) What is the cost per passenger with a tailwind of 50 miles per hour