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 sold an article at $ 100 with 10 % profit . then find its cost price ? 
Options: a ) $ 120 , b ) $ 100 , c ) $ 91 , d ) $ 72 , e ) $ 69

A: c
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Q: Problem: what is 50 % of 40 % of 1200 grams ? 
Options: a ) 450 gms , b ) 100 gms , c ) 300 gms , d ) 240 gms , e ) none of these

A: d
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Q: Problem: a number increased by 10 % gives 660 . the number is ? 
Options: a ) 200 , b ) 300 , c ) 500 , d ) 600 , e ) 400

A:
d
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