Hello Savannah,
Since there's a 3% growth every year, it means that to find the population from one year to the next, you would multiply by (100% + 3%) or 103%, which is 1.03 as a decimal
The formula that would represent the population size is: P(t) = P0 * (1.03)t
where P0 is the initial population, P(t) is the final population, and t is the time it takes for the population to equal P(t)
You're asked to find the population in 24 years, so P(24):
P(24) = 300000 * (1.03)24
P(24) = 300000• (2.0327941) = 609,838 ---> the population of this city in 24 years would be 609,838
Cheers.