Kids so that minimizes the amount per kid. I understand education spending overall is actually proportionally more for similar sized states. You’d have to tax citizens a lot more to get them close to spending per kid in other states, which is tenuous (Utah has actually spent much, much more in recent years but still is at the bottom because the denominator is so big) But looking at actual education outcomes, Utah fares far better than the average and punches well above its weight. So that explains a part of why Utah education spending (at least per kid) is at the bottom.
One other thing that doesn’t get discussed is I understand that Utah has the #1 school volunteer rate which contribute to overall education resources but doesn’t show on the spending side (and spending per child).