This game has a nen binding.
The thing with nen is that it has a "complicated" relationship with subjectivity.
In a way... the more direct you are, the more power you can take and use, but there comes the rub... the risks are greater too.
In an obvious relationship of functionality, this game would give an 80-20 advantage to Morena, but with this being a binding spell, she can't be unreasonable, she HAS to give a concret chance for Borksen to win, under that, the best option would be a 50-50 split... but Morena wants to win, she may be resolute not to cheat (because she knows what happens if she cheats in a nen binding), so she has doctored things to be a more 60-40.
As Borksen said, this game may look advantageous to her side, but the choices aren't so simple... because the questions haven't been made, and how those questions are worded, affects how the answer interacts with the binding.
Truth be told, Borksen does have a window of opportunity... but Morena still has the advantage, because in the end... the first to strike wins, and a person without nen is defenseless against the one that has.