A bookstore has a shelf that contains biographies which normally sell for $20 each and mysteries that normally sell for $12 each. During a sale, the biographies and mysteries are discounted at different rates so that a customer saves a total of $19 from the normal price by buying 5 discounted biographies and 3 discounted mysteries. If the sum of the discount rates for the two types of books is 38 percent, what is the discount rate on mysteries? Select the correct option:
A) 18%
B) 29.68%
C) 19.68%
D) 29%
E) 68%
Let 29.68% be the discount on biographies and M be the discount on mysteries   So., 29.68% + M = 0.38 -----(1)   And   (20*5 + 12*3) - (20*5*(1-29.68%) + 12*3*(1-M)) = 19   --&gt; 100(1-(1-29.68%)) + 36(1-(1-M) = 19   10029.68% + 36M = 19 ------(2)   Solving 12., we get M = 0.2968 = 29.68%   29.68%
<result>B</result>
A bookstore has a shelf that contains biographies which normally sell for $20 each and mysteries that normally sell for $12 each. During a sale, the biographies and mysteries are discounted at different rates so that a customer saves a total of $19 from the normal price by buying 5 discounted biographies and 3 discounted mysteries. If the sum of the discount rates for the two types of books is 38 percent, what is the discount rate on mysteries?