Question

In 1980, the number of African elephants was 1,200,000 but that number was decreasing 5.25% a year. How many African elephants were there in 1988? Round your answer to the nearest whole number.

Answer 1

use the geometric progression formula
\[\huge a_n = a_1 r^{n-1}\]

in this case, a1 is 1,200,000
r is 0.0525
n is 8 (because 1988 is 8 years after 1980)

so you have \[\huge a_n = (1,200,000) (0.0525)^{8-1}\]
solve that and you'll get your answer