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: solve the quickfire maths brain teaser â ˆ š 25 % = ? 
Options: a ) 30 % , b ) 40 % , c ) 50 % , d ) 19 % , e ) 29 %

A: c
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Q: Problem: simple interest on a certain sum at a certain annual rate of interest is 1 / 9 of the sum . if the numbers representing rate percent and time in years be equal , then the rate of interest is : 
Options: a ) 5 , b ) 8 , c ) 3 1 / 3 , d ) 2 2 / 3 , e ) none of these

A: c
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Q: Problem: how many liters of water must be evaporated from 50 liters of a 3 - percent sugar solution to get a 20 - percent solution ? 
Options: a ) 45 , b ) 33 1 / 3 , c ) 27 , d ) 16 2 / 3 , e ) 15

A:
a
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