ShreyasJavahar wrote:
Bunuel wrote:
The manufacturer’s suggested retail price (MSRP) of a certain item is $60. Store A sells the item for 20 percent more than the MSRP. The regular price of the item at Store B is 30 percent more than the MSRP, but the item is currently on sale for 10 percent less than the regular price.
Hello
VeritasKarishma,
I took the "10 percent less than the regular price" to mean that 10 percent of the regular price was subtracted from the marked up price, similar to how one would interpret "5 dollars less than 10". I've seen other questions that require interpreting the "percent less" as a subtraction and not as a multiplier.
Could you please provide some insight into how to ascertain what warrants the subtraction of a percentage of something and what warrants the use of a multiplier?
What you did is correct. Multiplier and addition/subtraction are equivalent concepts. Look here:
MSRP is 60.
Marked up price of store B = 60 + 30% of 60 = 60 + 60*(30/100) = 60 * (1 + 3/10) = 60 * (13/10) = 78
Discounted price = 78 - 10% of 78 = 78 * ( 1 - 10/100) = 78*(9/10) = 70.2
The addition/subtraction leads up to the multiplier by algebraic manipulation. Depending on given data, one of the other method comes out to be easier.
For example, if I know the multiplication table of 13, I can arrive at 78 directly. If I don't, I know that 10% of 60 is 6 so 30% will be 18 and hence 30% more than 60 will be 78.
Similarly, for discounted price, I know 10% of 78 is 7.8. So subtracting that from 80 gives me 70.2. This is easier than multiplying 78 with 9.
Multipliers are very useful in situations of successive percentage changes with suitable percentages. e.g. if there is an increase of 20% and a decrease of 37.5%, we will multiply by 6/5 and by 5/8 which will give A * (6/5)*(5/8) = A * (3/4) which is simply a decrease of 25% (an easier calculation)
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Karishma
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