Let's start by defining some variables:
P0 = 151000 // initial population in 2013
r = 0.05 // constant annual growth rate
t = 7 // number of years from 2013 to 2020
The exponential model for the population can be written as follows:
y = P0 * (1 + r)^t
Substituting in the values we get:
y = 151000 * (1 + 0.05)^7
y ≈ 209749
Therefore, the exponential model that represents the population of the city t years after 2013 is y = 151000 * (1 + 0.05)^t, and the estimated population in 2020 is about 209,749.
Note that the result is an estimation, and can be affected by various factors, such as migration and mortality rates, that are not accounted for in the model.