The relation between the population of the USA and the time in years after 2010 will be linear as the increase in population is constant for every year since 2010 which is 2.31 million.
So, we can model the population P in million as a function of time(t) in years since 2010 as
P = 309.35 + 2.31t ....... (1)
Now, for t = 0 i.e. in the year 2010, the population will be obtained from equation (1) to be 309.35 million.
