An investigation is done to find out how effective different biological washing powders are at digesting protein. Four equal-sized cubes of cooked egg white (protein) are cut and their masses measured. The cubes of protein are then placed in test-tubes containing 10 cm³ of solutions of four different biological washing powders of the same concentration. The cubes of protein are left in the solutions at room temperature. After 24 hours, the cubes of protein are removed from the test-tubes and their masses remeasured. [Table 35.1] What is the percentage decrease in mass of the cube of protein in the most effective washing powder given to one decimal place?

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