A cookie recipe calls for 3/4 cup of granulated sugar and 1/2 cup of powdered sugar. If Jacob doubles the recipe, what is the total number of cups of granulated sugar and powdered sugar he will need?
If Jacob doubles the recipe, he will need 3/4 x 2 = <<3/4*2=1.5>>1.5 cups of granulated sugar.
He will also need 1/2 x 2 = <<1/2*2=1>>1 cup of powdered sugar.
Therefore, Jacob will need a total of 1.5 + 1 = <<1.5+1=2.5>>2.5 cups of granulated sugar and powdered sugar. Answer: \boxed{2.5}.
To find the total amount of granulated sugar and powdered sugar needed when Jacob doubles the recipe, we need to multiply the amount of each ingredient by 2.
For granulated sugar:
1 recipe requires 3/4 cup
2 recipes require 2 * (3/4) cups = 6/4 cups = 3/2 cups
For powdered sugar:
1 recipe requires 1/2 cup
2 recipes require 2 * (1/2) cups = 2/2 cups = 1 cup
Therefore, Jacob will need a total of 1.5 cups of granulated sugar and 1 cup of powdered sugar when he doubles the cookie recipe.