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 farmer spent $ 35 on feed for chickens and goats . he spent 40 % money on chicken feed , which he bought at a 40 % discount off the full price , and spent the rest on goat feed , which he bought at full price . if the farmer had paid full price for both the chicken feed and the goat feed , what amount would he have spent on the chicken feed and goat feed combined ? 
Options: a ) $ 37.80 , b ) $ 38.50 , c ) $ 39.20 , d ) $ 44.33 , e ) $ 40.60

A: d
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Q: Problem: in an office , 20 percent of the workers have at least 5 years of service , and a total of 16 workers have at least 10 years of service . if 90 percent of the workers have fewer than 10 years of service , how many of the workers have at least 5 but fewer than 10 years of service ? 
Options: a ) 32 , b ) 64 , c ) 50 , d ) 144 , e ) 160

A: a
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Q: Problem: john had a stock of 1000 books in his bookshop . he sold 75 on monday , 50 on tuesday , 64 on wednesday , 78 on thursday and 135 on friday . what percentage of the books were not sold ? 
Options: a ) 59.8 % , b ) 23.8 % , c ) 66.5 % , d ) 34.9 % , e ) 43.5 %

A:
a
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