Answer:
[tex]\frac{8}{9}[/tex]
Step-by-step explanation:
Since there are 432 tickets total and Gabriela bought 48, the chances of Gabriela not winning the grand prize is equal to the chance of any of the tickets she did not buy getting drawn. If she bought 48, then she did not buy 432-48=384 tickets. The chances of any of these being drawn is:
[tex]\frac{384}{432}=\boxed{\frac{8}{9}}[/tex]
