SOLUTION: A car stereo is on sale at a 20% discount. The original amount of the stereo is $8500. If the purchase will include a 12% tax, it would come out cheaper if the discount is applied

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: A car stereo is on sale at a 20% discount. The original amount of the stereo is $8500. If the purchase will include a 12% tax, it would come out cheaper if the discount is applied       Log On


   



Question 1187621: A car stereo is on sale at a 20% discount. The original amount of the stereo is $8500. If the purchase will include a 12% tax, it would come out cheaper if the discount is applied before the tax is added to the price. Is it true or false?
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
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A car stereo is on sale at a 20% discount. The original amount of the stereo is $8500.
If the purchase will include a 12% tax, it would come out cheaper if the discount is applied
before the tax is added to the price. Is it true or false?
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Let's calculate both values.


    (1)  First discount, then tax.  You should pay  6500*(1-0.2)*1.12 = 6500*(0.8*1.12) = 6500*0.896 = 5824 dollars.



    (2)  First tax, then discount.  You should pay 6500*1.12*(1-0.2) = 6500*(1.12*0.8) = 6500*0.896 = 5824 dollars.



As you see, the final amount to pay is the same.



What is interesting, the reducing multiplicative factor is the same in both cases:  


    it is  0.8*1.12 = 1.12*0.8 = 0.896  in both cases.


It is the key.

Solved.

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On chain discounts,  see the lesson
    - Percentage problems on chains of discounts
in this site.