Need help asap i hate these type of questions but i know it isnt to hard

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

I'm confused on this could anyone me and show me what i need to do to solve it.

According to the 2008 u. s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.