Average Rate of Change - Populuation

The population of a town is modelled by P(t) = 6t^2 + 110t + 3000, where P is the population and t is the number of years since 1990.

a) find the average rate of change in population between 1995 - 2005

b) Estimate the rate at which the population is chaning in 2005.

* I am currently taking Calculus and Vectors for the first time through corrospondance, with no textbook or other material support. I would really appreciate any help.

Thank you very much in advance.