If neighborhood A has 30 homes and increases by 20% each year, we first need to multiply 30 by 20%, which is 6. Next, add the six new houses to the original 30, which is 36. If neighborhood B has 45 homes, but gets three more, that is 48. After one year, neighborhood B has more homes than neighborhood A. Neighborhood A will have more houses than neighborhood B after 4 years. (Five years if you count the starting year.)