Let x represent the number of days Student J has been reading.
Student J's equation: 20x
Student K's equation: 30(x-2)
We want to find the number of days when both students have read the same number of pages.
20x = 30(x-2)
20x = 30x - 60
-10x = -60
x = 6
Therefore, it will take 6 days for both students to have read the same number of pages.