A publisher 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 35 percent, what is the discount rate on mysteries book?  Answers.
A) 10%  B) 40%  C) 35%  D) 30%  E) 25%
Let B be the discount on biographies and M be the discount on mysteries   So., B + M = 0.35 -----(1)   And   (20*5 + 12*3) - (20*5*(1-B) + 12*3*(1-M)) = 19   --&gt; 100(1-(1-B)) + 36(1-(1-M) = 19   100B + 36M = 19 ------(2)   Solving 12., we get M = 0.25 = 25%   25%
<result>E</result>
A publisher 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 35 percent, what is the discount rate on mysteries book?