There are no unknowns, so the equation can be a evaluated: P(t)=189000*e^0.078=204,332. The interpretation appears to be that the percentage increase of the population is e^1.3% (=1.3085%) per year, so after 6 years the population of 189,000 grows to 204,332, according to the formula P(t)=pe^(rt) apparently.