Bookman purchased 30 copies of a new book released recently, 10 of which are hardback and sold for $20 each, and rest are paperback and sold for $10 each. If 14 copies were sold and the total value of the remaining books was 240, how many paperback copies were sold?  Pick one
A) 8  B) 12  C) 6  D) 4  E) 5
The bookman had 10 hardback ad  30-10= 
<gadget id="calculator"> 30-10</gadget>
<output>20</output>
20 paperback copies;   14 copies were sold, hence  30-14= 
<gadget id="calculator"> 30-14</gadget>
<output>16</output>
16 copies were left. Let # of paperback copies left be p then 10p+20(16-p)=240 --&gt; 10 p=80 --&gt; p=8   # of paperback copies sold is 20-8= 
<gadget id="calculator">20-8</gadget>
<output>12</output>
12   Answer: 12
<result>B</result>
Bookman purchased 30 copies of a new book released recently, 10 of which are hardback and sold for $20 each, and rest are paperback and sold for $10 each. If 14 copies were sold and the total value of the remaining books was 240, how many paperback copies were sold?