Warm-Up A biologist is studying the exponential growth of a colony of bacterial cells. The table gives the number of cells, y, in the
colony over time, x, in hours.
Time, x (hours) Number of Cells, y
0
100
1
200
2
400
h
6,400
Replace the values of A, b, x, and y to write an exponential equation that represents the number of cells present at h hours.
A(b)^x = y

The weekly amount spent by a company for travel has an approximately normal distribution with mean = $550 and standard deviation = $40. a) what is the probability that the actual weekly expense will exceed $570 for more than 20 weeks during the next year? (note: one year = 52 weeks) b) what is the probability that actual weekly expenses exceed $580 for 10 or more, but 16 or fewer weeks during the next year?