The amount of fat in an ounce of food A plus the amount of protein in an ounce of food A is 100 grams. The amount of protein in an ounce of food A minus twice the amount of fat in an ounce of food A is 10 grams. How many grams of protein are there in an ounce of food A? 1. 30 2. 45 3. 50 4. 70