Population growth the population of knoxville is 500,000 and is increasing at the rate of 3.75% each year. approximately when will the population reach 1 million?

Current population = 500,000
Populaton is
500,000 * (1.0375) after 1 year
500,000 * (1.0375)² after 2 years 
...
500,000 * (1.0375)ˣ after x years

Therefore when the population reaches a million,
500,000 * (1.0375)ˣ = 1,000,000
1.0375ˣ = 2
x ln(1.0375) = ln(2)
x = ln(2) / ln(1.0375) = 18.83 years

 18.8 years, or approximately 19 years.