Percentage Discount given an Original Price of $35 and a Sale Price of $20

Discount Rate = 1 –  
Discount Rate = 1 – 0.5714
Discount Rate = 0.4286
0.4286 Converted to a Percent: 0.4286 = 42.86%
Percentage Discount given an Original Price of $35 and a Sale Price of $20 = 42.86%
Note: Reduction in Price = $35 – $20 = $15