The count in a bacteria culture was 800 after 15 minutes and 1700 after 30 minutes. Assuming the count grows exponentially,

Question

The count in a bacteria culture was 800 after 15 minutes and 1700 after 30 minutes. Assuming the count grows exponentially,

What was the initial size of the culture?   

Find the doubling period.   

Find the population after 70 minutes.   

When will the population reach 13000. 

Answer 1

800 = ab¹⁵

1700 = ab³⁰

Divide bottom by top

2.125 = b¹⁵

1.051535475 = b

800 = a₀(1.051535475)¹⁵