Let the current retail price = 100.

1st discount = 10%. Hence New price = 90.

2nd discount = 20% on New price., Hence, Final price = 90-18 = 72.

Hence, Net discount on the original price is 28%. Hence, C
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If we REDUCE a price by 10%, then the reduced price is 90% of the original price.
Likewise, if we REDUCE a price by 20%, then the reduced price is 80% of the original price.
If we REDUCE a price by 30%, then the reduced price is 70% of the original price.
.....etc.
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Let $100 be the original price.
So, a 10% reduction means the new price = (0.9)(100) = $90
A further 20% reduction means the new price = (0.8)(0.9)(100) = $72
This represents a $28 discount off the original $100
28/100 = 28%

Answer:

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Two methods to solve this one =>
Let CP be x => SP=x[1-10/100][1-20/100]=72x/100
discount amount = x=72x/100=28x/100
Discount percent = discount/CP *100 = 28%
Smash that C


Method 2 =>
Let CP=100
SP=100[1-10/100][1-20/100]=72
hence Discount = 28
Discount percent = 28%
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Discount = 1-0.9*0.8=1-0.72=0.28=28%
Answer choice C.

This is an example in the lower range that wants to trick people into forgetting about the joint effect of the two discounts and thus simply adding them to get 30%.
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