By selling

By selling an article for $21, a trader loses a percentage equal to the cost price of the article. Find the cost price.

Final Answer:

x1 =  70 USD
x2 =  30 USD

Step-by-step explanation:

 100 (x21)/x = x  100 (x21)=x2  100 (x21)=x2 x2+100x2100=0 x2100x+2100=0  a=1;b=100;c=2100 D=b24ac=1002412100=1600 D>0  x1,2=2ab±D=2100±1600 x1,2=2100±40 x1,2=50±20 x1=70 x1=x2=30=70 USD

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You need to know the following knowledge to solve this word math problem:

algebrabasic operations and conceptsUnits of physical quantitiesGrade of the word problem

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