(Please Help) Which equation represents the number of years (t) that it takes $200 to grow to $500 if it is growing at an exponential rate of 15% per year?

Answer:
A
Step-by-step explanation:
in 1 years it grows 15% of $200= $30+200=$230
in x yrs it grows to $500
.... number of yrs= 500/230= 2.17 yrs