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'.

[Q]: Problem: a shopkeeper has 100 kg of apples . he sells 50 % of these at 25 % profit and remaining 50 % at 30 % profit . find his % profit on total . 
Options: a ) 27.5 % , b ) 25.6 % , c ) 31.5 % , d ) 35.9 % , e ) 29.5 %
[A]: a


[Q]: Problem: calculate how many seconds it will take for 4 bells to toll together again , given that they begin to toll together respectively at the intervals of 9 , 10 , 14 and 18 seconds . ? 
Options: a ) 636 , b ) 631 , c ) 633 , d ) 610 , e ) 630
[A]: e


[Q]: Problem: a pair of articles was bought for $ 810 at a discount of 10 % . what must be the marked price of each of the article ? 
Options: a ) $ 300 , b ) $ 500 , c ) $ 350 , d ) $ 450 , e ) $ 600
[A]:
d