What was the percent increase in the population in South America from 1900 to 2000?

Question

1900-38,000,000, 1950-111,000,000,
2000-515,000,000

Answer 1

(515,000,000 - 38,000,000)/38,000,000, converted to %

You do not need the 1950 population to compute it.

Answer 2

515,000,000 - 38,000,000 = 477,000,000

477,000,000 / 38,000,000 = 12.5526 = 1255.26%