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Here's a word problem having to do with percentages, and the answer doesn't make sense. A furniture store is selling a desk for $300. If the store makes a 25% profit on the sale, what is the store's cost for the desk? The answer is $240 but how?


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up vote 1 down vote accepted

Let us say that $x$ is the cost for the store. The store makes a profit of $25$% which means that the selling price is $1.25 x$; so $1.25 x=300$ then $x=300/1.25=240$.

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Let's say the cost of the desk for the store is 100%. We know 25% more than that is \$300. Hence, 125% of the cost price of the desk is \$300, and the original price is therefore $100\times \frac{\$300}{125}$. Since $\$300/125$ = 1% of cost price, and then we just multiply by 100 to find the original 100%.

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Use the formula:

$$\frac{\text{percent of change}}{100} = \frac{\text{change in price}}{\text{original price}}$$

Let $x$ = the original price.


$$\frac{1}{4} = \frac{300-x}{x}$$

$x = $ $240.

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Thanks, skullpatrol. BTW, how do you enter the equations on this site? – Alex Mar 31 '14 at 4:20
This may help :-) – skull petrol Mar 31 '14 at 12:28

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