Answer
The population of City A is growing faster than City B.
Work Step by Step
Since the population of City A is growing by a constant continuous percent rate, the function can be modelled as an exponential function. Let $a= P_0$ and $b= 0.15$
$$
P=P_0 e^{0.15 t}=P_0\left(e^{0.15}\right)^t=P_0(1.1618)^t
$$
From this, we see that $b= 1.1618$. The population increases by about $16.18\%$ per year. Hence, the population of City A is growing faster than City B.
