In 2000 the population of a country reached 1 billion, and in 2025 it is projected to be 1.5 billion. (a) Find values for C and a so that P(x)=Ca x-2000 models the population of a country in year x. (b) Estimate the country's population in 2008. (c) Use P to determine the year when the country's population might reach 1.6 billion. (a) C (Type an integer or decimal rounded to five decimal places as needed.) a=(Type an integer or decimal rounded to five decimal places as needed.) (b) The population in 2008 was billion. (Round to two decimal places as needed.) (c) The country's population might reach 1.6 billion in the year (Type a whole number.)