I think the “and” there is that by default, the costs to housing students would be lower, schools generally only need to provide one meal as opposed to 3, do not have to provide comprehensive medical and dental, and only must provide staff and other things like utilities for 6-8 hours a day on average. So even if we spent the same amount dollar per hour of time spent on students and convicts, the yearly total per convict would average out to be higher.
Of course- it isn’t an either or proposition- we can increase funding to students without decreasing funding to prisons, or change the budgets of either or institutions without effecting the other- ignoring the obvious question of where the money would come from- which is another matter entirely.
And.... that also leaves out making changes to both systems and of law and social reform- from the “less radical”: transition to a prison system based more on rehabilitation, less incarceration for non violent offenders etc. to the extremely radical- such as to offer training and certification as teachers to qualifying prisoners who have long term sentences, and then make part of their prison program and rehabilitation the teaching of kids at inmate labor rates or even (ethically questionable) at no pay but in exchange for the learning and privileges an inmate would gain through such a program. For each such inmate you then need one less private market teacher who requires benefits which duplicate what you are already paying to care for convicts, and salary which you an effectively make $0 for a convict teacher. Then the salary budget could be used for other things in the school system and our prison system could have a net positive for society.
Not advocating it- just saying that the two don’t have to be related, and if we do want to relate them we can do so in many ways beyond an obvious cost equivalency; which to what I read as the original point- is not an “apples to apples” comparison.
Improving school equipment.