Question

Growth of Bacteria 

The growth rate of Escherichia coli, a common bacterium found in the human intestine, is proportional to its size. Under ideal laboratory conditions, when this bacterium is grown in a nutrient broth medium, the number of cells in a culture doubles approximately every 20 min. 

(a) If the initial population is 20, determine the function Q(t) that expresses the growth of the number of cells of this bacterium as a function of time t (in minutes). 

(b) How long would it take for a colony of 20 cells to increase to a population of 1 million? (Round your answer to the nearest whole number.) 

(c) If the initial cell population were 200, what is our model? 

Resale Value 

Garland Mills purchased a certain piece of machinery 4 years ago for $500,000. Its present resale value is $280,000. Assuming that the machine's resale value decreases exponentially, what will it be (in dollars) 5 years from now? (Round your answer to the nearest dollar.) 

Answer 1