Question 1139004: On Wednesday, the price of Thanksgiving pies was discounted 20%. On Thursday, the pies were discounted an additional 70%. What was the combined percent discount?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let the original purchase price of the pie be equal to x.
with a 20% discount, the sale price of the pie was (1 - .20) * x = .80 * x.
with a 70% discount on the sale price, the final sale price was (1 - .70) * .80 * x = .30 * .80 * x = .24 * x.
the original price was x.
the final price was .24 * x.
the overall discount was 1 - .24 = .76 * 100 = 76%.
the first discount was .20 * x, making the sale price equal to x - .20 * x = .80 * x.
the second discount was .70 * .80 * x = .56 * x, making the sale price equal to .80 * x - .56 * x = .24 * x.
add up the discounts, you get .20 + .56 = .76 = 76%.
as an example, assume the original price of the pie was 15 dollars.
with a 20% discount, the first sale price was 15 - .20 * 15 = 12 dollars.
with a 70% discount on the sale price of 12 dollars, the second sale price was 12 - .70 * 12 = 3.6 dollars.
the original price was 15 dollars.
the final sale price was 3.6 dollars.
the discount was 15 - 3.6 = 11.4 dollars.
11.4 / 15 = .76 * 100 = 76% overall percent discount.
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