Answer:
2,396,000 adults were incarcerated in 2013.
Step-by-step explanation:
The number of incarcerated adults N (measured in thousands) in a certain country can be approximated by the equation
N = -2.7x² + 72.4x + 1911
where x is the number of years since 2000.
In 2013, x = 2013 - 2000 = 13, and the number of incarcerated adults was
N = -2.7(13)² + 72.4(13) + 1911
N = -456.3 + 941.2 + 1911
N = 2,396
2,396 thousands (2,396,000) adults were incarcerated in 2013.