A certain store sells all maps at one price and all books at another price. On Monday the store sold 12 maps and 10 books for a total of $42.00, and on Tuesday the store sold 20 maps and 15 books for a total of $70.00. At this store, how much less does a map sell for than a book? Pick one: A) $0.25 B) $0.50 C) $3.5 D) $2.5 E) $l.25
12x+10y=42   20x+15y=70   multiply eq 1 by 5 and eq 2 by 3   60x+50y=42*5   60x+45y=70*3   subtracting 1 from 2   5y=210-210= 
<gadget id="calculator">210-210</gadget>
<output>0</output>
0   therefore   x=3.5   difference in price =3.5   $3.5
<result>C</result>
A certain store sells all maps at one price and all books at another price. On Monday the store sold 12 maps and 10 books for a total of $42.00, and on Tuesday the store sold 20 maps and 15 books for a total of $70.00. At this store, how much less does a map sell for than a book?