Answer:
a) 
b) 
c) 
Step-by-step explanation:
For this case we have the following differential equation:

And if we rewrite the expression we got:

If we integrate both sides we have:

Using exponential on both sides we got:

Part a
For this case we know that p(0) = 770 so we have this:


So then our model would be given by:

And if we want to find at which time the population would be extinct we have:


Using natural log on both sides we got:

And solving for t we got:

Part b
For this case we know that p(0) = p0 so we have this:


So then our model would be given by:

And if we want to find at which time the population would be extinct we have:


Using natural log on both sides we got:

And solving for t we got:

Part c
For this case we want to find the initial population if we know that the population become extinct in 1 year = 12 months. Using the equation founded on part b we got:


Using exponentials we got:



