Percentage Discount given an Original Price of $400 and a Sale Price of $240

Discount Rate = 1 –  
Discount Rate = 1 – 0.6
Discount Rate = 0.4
0.4 Converted to a Percent: 0.4 = 40%
Percentage Discount given an Original Price of $400 and a Sale Price of $240 = 40%
Note: Reduction in Price = $400 – $240 = $160