I sold a book at a profit of 12%. Had I sold it for $18 more, 18% would have been gained. Find the cost price?
Pick
A) $100  B) $250  C) $300  D) $200  E) $180
118% of cost - 112% of cost = $18   6% of cost = $18   cost = 18*100/6= 
<gadget id="calculator">18*100/6</gadget>
<output>300</output>
$300   Answer is $300
<result>C</result>
I sold a book at a profit of 12%. Had I sold it for $18 more, 18% would have been gained. Find the cost price?