P (percentage) * X = Y; Substitute the values -
P * 1.20 = .80
1.20P = .80 (divide both members of the equation by 1.20
P = .67
To get the percentage, move the decimals of .67 two places to the right or multiply it by 100. Therefore, the percentage of the sale is 67%.
To check-
1.20 * 67% = .804 or 80.