Answer:
The original recipe calls for 1 1/4 cups of dip and 1/2 cup of veggies, so you + both together which is a total of 1 3/4 cups of ingredients.
If Austin wants to use 1 cup of veggies instead of 1/2 cup, he needs to double the recipe. To keep the same ratio of dip to veggies, he will also need to double the amount of dip.
1 3/4 cups (original recipe) x 2 = 3 1/2 cups
Therefore, Austin will need 3 1/2 cups of dip to make the recipe using 1 cup of veggies.