Answer
The same enrollment ( $22,300$ ) will be achieved in 2019.
Work Step by Step
Let $ x=$ the number of years after 2010.
Enrolled at college A, after x years = $13,300+1000x $
Enrolled at college B, after x years = $26,800-500x $
We want to find x when these two are equal.
$13,300+1000x=26,800-500x \qquad $ ... add $500x-13,300$
$1000x+500x=26,800-13,500\qquad $
$1500x=13,500\qquad $ ... divide with 1500
$ x=9$
The two colleges will have the same enrollment
$9$ years after 2010, in 2019.
To calculate the enrollment, substitute $x=9$ into one of the expressions
$13,300+1000(9)=22,300$
