Answer:
5820
Step-by-step explanation:
You want to know the number of bacteria initially, if the count after 8 hours is 10000, and the growth rate is 7% per hour.
Exponential equation
The population p can be described using the given numbers by the equation ...
p = p₁·(1 + growth rate)^(t -t₁)
where (t₁, p₁) tells the population p₁ at some time t₁.
Here, the population is 10000 when t=8, so we have ...
p = 10000·(1 +0.07)^(t -8)
Initial population
The initial population of bacteria is the value of p at t=0:
p = 10000·(1.07^-8) ≈ 5820
There were 5820 bacteria in the original sample.
