Answer :
Since Mary spent a third of her weekly allowance playing arcade games and she spent $4.32. Let "a" be her weekly allowance, then (1/3)a = $4.32. Thus she still has:
a - (1/3)a = (2/3)a = (1/3)a + (1/3)a = (1/3)a + $4.32
then the answer is option a.
