im not so good on this i need help its precalculus

Question

The count in a bacteria culture was 700 after 10 minutes and 1900 after 30 minutes. Assuming the count grows exponentially,

What was the initial size of the culture?   ___

Find the doubling period.   ___

Find the population after 110 minutes.   ___

When will the population reach 11000. ____

Answer 1

f(x) = ar^x

f(10) = 700

700 = ar¹⁰

f(30) = 1900

1900 = ar³⁰

2.714 ≈ r²⁰

Solve for r and substitute into either function to determine a