20 * 1000 = 20000 & lt； 22500 describes x & gt20,
More than x-20 people
( 1000-20(x-20))*x=22500
1000x-20x(x-20)=22500
-20x^2+ 1000x+400x=22500
x^2-70x+ 1 125=0
(x-25)(x-45)=0
X=25 or x=45
Test x=25 per capita1000-5 * 20 = 90025 * 900 = 22500.
When x=45, per capita 1000-25*20=500 (but 800 per capita is the least, so it is discarded).
A ***25 people