For this problem, you have already determined the cell density of a culture in a flask. You take a 1 ml volume containing 10 cells, and add it to a 10 ml tube of media to get 1 cell/ml. You set up 12 of these tubes all with 1 cell/ml (so you have enough to make a growth curve).
These tubes are incubated for 12 days total, and you sample 1 ml each day from the appropriate tube (day 1 is tube 1, day 2 is tube 2, etc.) and spread plate on media plates (1 ml).

Cell numbers on the plates are as follows.
Day - 1 1 CFU/ml Day - 7 10000
Day - 2 10 Day - 9 1000
Day - 3 100 Day - 10 100
Day - 4 1000 Day - 11 10
Day - 5 10000 Day - 12 10
Day - 6 10000

A. How fast was the growth during exponential phase?