A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 65 cells. (The tolerance is 1% unless your instructor states otherwise.)

(a) Find the relative growth rate.

(b) Find an expression for the number of cells after t hours.

(c) Find the number of cells after 6 hours.

(d) Find the rate of growth after 6 hours.

(e) When will the population reach 20,000 cells?

My answers are :

(a) k=

(b)

*P*(t)=

(c) 17039360 billion cells

(d)35432353 billion cells per hour

(e) 2.75 hour

According to the book only

**a and e** are correct.

Any help