Part A. To find the growth factor of the town, you can proceed like this
So, the growth factor for the town will be
For part B, exponential growth is modeled by the equation
So, you have
For part C, you need to find the population in 2011, so
Then, plug in the equation found x = 5
Therefore, the population of Tewksbury in 2011 will be 27874 people.