a school starts with 300 students, each year they exponentially increase by .9%, what is the equation

Question

in the question you make an equation, would it be 

200(1.9)^x

200(1.09)^x

200(1.009)^x

Answer 1

For exponential increase: N=N₀a^t (with N₀ the number at t=0 and t in years).

After 1yr, N=N₀+.9%N₀=1.009N₀ so N/N₀=1.009

Since N=N₀a^t after 1yr (t=1) a=N/N₀=1.009

so N=300(1.009)^t

Answer 2

I'm not sure why you have 200 starting each of your answers, instead of 300.

.9% = .009

300(1.009)^x