Problema Solution

To begin a bacteria study a petri dish had 2600 bacteria cells. Each hour since, the number of cells has increased by 7.4%

Let t be the number of hours since the start of the study. Let y be the number of bacteria cells

Write an exponential function showing the relationship between y and t.

Answer provided by our tutors

at the start:


t = 0


y = 2600


after 1 hour:


t = 1 hr


y = 2600 + 0.074*2600


y = 2600(1 + 0.074)


after 2 hours:


t = 2 hr


y = 2600(1 + 0.074) + 2600(1 + 0.074)*0.074


y = 2600(1 + 0.074)^2


after 3 hours


t = 3 hr


y = 2600(1 + 0.074)^3


thus the exponential function is:


y = 2600(1 + 0.074)^t


we can also prove the above equation using the method of Mathematical induction.