Answer:
469,532 Americans
Explanation:
The number of Americans in prison for drug related offenses from 1980 = 40,900
Percentage increase = 1048%
Let the number of people in prison for drug related offenses in 2015 be 'x'
Percentage increase =

=

x = (1048 × 409) +40,900
x = 428632 +40,900
x = 469532
469,532 Americans were in prison for drug related offenses in 2015.