A pair of articles was bought for $720 at a discount of 10%. What must be the marked price of each of the article?
Select: A) $300 B) $500 C) $350 D) $400 E) $600
S.P. of each of the article = 720/2= 
<gadget id="calculator">720/2</gadget>
<output>360</output>
$360   Let M.P= $x   90% of x = 360   x = 360*100/90= 
<gadget id="calculator">360*100/90</gadget>
<output>400</output>
$400   Answer is $400
<result>D</result>
A pair of articles was bought for $720 at a discount of 10%. What must be the marked price of each of the article?