From the dawn of humanity to 1830, world population grew to one billion people. In 100 more years (by 1930) it grew to two billion, and 3 billion more were added in only 60 years (by 1990). In 2016, the estimated world population was 7.4 billion with a relative growth rate of 1.13%.

(A) Write an equation that models the world population growth, letting 2016 be year 0.
(B) Based on the model, what is the expected world population (to the nearest hundred million) in 2025? In 2033?