Answer:
See below.
Explanation:
Original Doubled Ingredient
1½ c ⟶ 3 c all-purpose flour (2×1½ = 2×1 + 2×½ = 2+1 = 3)
1 tsp ⟶ 2 tsp salt
1 Tbsp ⟶ 2 Tbsp sugar
1 Tbsp ⟶ 2 Tbsp baking powder
⅓ c ⟶ ⅔ c vegetable shortening
⅔ c ⟶ 1⅓ c buttermilk (2×⅔ = ⁴/₃ = 1⅓)