Comparing Individual Discounts to a Collective DiscountDate: 07/19/2005 at 07:33:52 From: Jay Subject: collective Discount vs individual discounts I am purchasing 2 books. If each book carries a 10% discount, will it always be the same as a 10% discount on the total price of the 2 books? Say Book A costs $100, Book B costs $100 and each has an 8% discount: Book A after discount - $92 Book B after discount - $92 Total = $184 Original Sales Price of Book A + Book B = $200 Discount 8% on $200 = $200-$16 = $184 So it's the same. I always thought individual discounts saved more money than collective discounts. Date: 07/20/2005 at 05:01:16 From: Doctor Ian Subject: Re: collective Discount vs individual discounts Hi Jay, Suppose the prices are A and B, and the discount is D. Then if we discount the books individually, we get (A - AD) + (B - BD) = A - AD + B - BD = A + B - AD - BD = (A + B) - (AD + BD) = (A + B) - (A + B)D Now let's apply the discount to both books at once: (A + B) - (A + B)D It's the same, isn't it? And we haven't even said what the prices or discounts are. So it must apply to any prices or discounts that we could make up. Does that make sense? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ Date: 07/21/2005 at 03:35:32 From: Jay Subject: Thank you (collective Discount vs individual discounts) It makes sense. Thanks very much, Dr. Ian. |
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