Many students from europe come to the united states for their college education.

from 1980 through 1990, the number s(in thousands), of european students

attending a college or university in the u. s. can be modeled by

s=0.05(t3 - 11ť + 45t +277), where t = ocorresponds to 1980.

in what year were there 31.35 thousand european students attended a u. s. college

or university?