(1-(9x^2+4)/12x) / (1/3x -1/2) +1

Achild has a box full of colored building blocks. she will choose one block without looking. the odds against choosing a blue block are 4/7. what is the probability of choosing a blue block? amanda is playing a role-playing game with her friends. she will roll dice to determine if her character unlocks a treasure chest. the probability of her character unlocking the treasure chest is 13/20. find the odds in favor of her character unlocking the treasure chest.