In a city in year 1990 have lived 700000 residents while in year 2000 there were 900000 residents

If you take the growth in population made at the same rate , find :

a) how much is the population grow of the city in the time period 1990-2000 ?

b) how much became the population number this year(2009) ?

c) when will the city have 1400000?