In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: a computer store offers employees a 10 % discount off the retail price . if the store purchased a computer from the manufacturer for $ 1200 dollars and marked up the price 10 % to the final retail price , how much would an employee save if he purchased the computer at the employee discount ( 10 % off retail price ) as opposed to the final retail price . 
Options: a ) 122 , b ) 132 , c ) 142 , d ) 152 , e ) 162
[EX A]: b

[EX Q]: Problem: the true discount on a bill due 9 months hence at 16 % per annum is rs . 150 . the amount of the bill is 
Options: a ) 1200 , b ) 1764 , c ) 1400 , d ) 1354 , e ) none of these
[EX A]: c

[EX Q]: Problem: 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 30 percent , what is the discount rate on mysteries ? 
Options: a ) 17.18 % , b ) 12 % , c ) 13 % , d ) 14 % , e ) 15 %
[EX A]:
a