Answer:25%Step-by-step explanation:The shirt on sale is P 100 less than the original price of 400.Percent Off is: (Final - Original)/(Original) = (300 - 400)/(400) = -100/400 = - 0.25 or - 25%-25% means the price was reduced by 25%, so the discount rate is 25% [The word "discount" implies the minus sign].