Question

The relative growth rate for a certain type of bacteria population is 85% per hour. A small culture has formed and in just 2 hours the count shows to be 12,500 bacteria in the culture. What is the initial number of bacteria in the culture?

Answer 1

Let us assume the initial number of bacteria in the culture = x

After 1 hour,

The number of bacteria = 185x/100

                                     = 1.85x

After 2 hours,

The number of bacteria = (185 * 1.85x)/100 

                                     = 3.42x

So

3.42x = 12500

x = 12500/3.42

  = 3654.97

  = 3655

From the above deduction, we can conclude that the initial number of bacteria in the culture is 3655