At Generic High School, in the year 2001, there were 20 students per every computer. In 2008, there were 4 students per computer. During which year were there 10 students per computer? Show your work.

let x = year - 2001

then 2008 is x= 7
let y = 20 - a x
4 = 20 - a*7
7 a= 16
a = 16/4
so
y = 20 - (16/4) x
10 = 20 - (16/4) x
(16/4)x = 10
x = 40/16 = 2.5 years after 2001
during 2003