Comment by phalf

But that's exactly what you did! You just counted which fraction of all kids is boys. You threw away that this is about pairs of kids, about april 1 on which one of them has their birthday and is a boy, and we want to know the sex of the other one. You already simplified by applying symmetry reductions. You could have just done print(1/2) and proclaimed that the output was 0.5 which therefore must be the solution.