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 total of $ 20,000 was invested in two certificates of deposit at simple annual interest rates of 6 percent and 8 percent , respectively . if the total interest on the two certificates was $ 1,440 at the end of one year , what fractional part of the $ 20.000 was invested at the higher rate ? 
Options: a ) 3 / 8 , b ) 2 / 5 , c ) 1 / 2 , d ) 3 / 5 , e ) 3 / 4
[EX A]: d

[EX Q]: Problem: if a man lost 4 % by selling oranges at the rate of 72 a rupee at how many a rupee must he sell them to gain 44 % ? 
Options: a ) 41 , b ) 48 , c ) 49 , d ) 44 , e ) 43
[EX A]: b

[EX Q]: Problem: a watch was sold at a loss of 10 % . if it was sold for rs . 500 more , there would have been a gain of 10 % . what is the cost price ? 
Options: a ) 1000 , b ) 2998 , c ) 2500 , d ) 2788 , e ) 2991
[EX A]:
c