The magician Moolin can make two different spells: Thunder— two vials of dragon tears and five vials of liquid pearl. Lightning— three vials of dragon tears and two vials of liquid pearl. Moolin has vials of dragon tears and liquid pearl at a ratio of 4 to 5. If Moolin wants to use up all of its ingredients, what ratio of Thunder to Lightning should he make? Please give the answer as a fraction in the simplest term (e.g. if the ratio is 2:3, write 2/3).