In the Pearson Square Method, how are the two component amounts typically combined to determine proportions?

• A. They are subtracted from the diagonal
• B. They are added along the top edge
• C. They are multiplied and then divided
• D. They are placed on opposite corners and averaged

Answer: (A)

The Pearson Square determines how much of each ingredient to mix by using differences from the desired value. You compare each ingredient’s percentage to the target percentage and form two differences, which are found by subtracting across the diagonal of the square. These two differences become the proportions for the final blend—the larger difference corresponds to the ingredient farther from the target, and the two differences are used as the mixing ratio. Concretely, the amount of the first ingredient to use is the difference between the desired percentage and the second ingredient’s percentage, and the amount of the second ingredient is the difference between the first ingredient’s percentage and the desired percentage. This subtraction method yields the correct proportions for achieving the target value.