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 gambler has won 40 % of his 30 poker games for the week so far . if , all of a sudden , his luck changes and he begins winning 80 % of the time , how many more games must he play to end up winning 60 % of all his games for the week ? 
Options: a ) 20 , b ) 25 , c ) 30 , d ) 35 , e ) 40

A: c
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Q: Problem: a baseball card decreased in value 10 % in its first year and 10 % in its second year . what was the total percent decrease of the card ' s value over the two years ? 
Options: a ) 19 % , b ) 30 % , c ) 32 % , d ) 36 % , e ) 72 %

A: a
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Q: Problem: running at the same constant rate , 6 identical machines can produce a total of 390 bottles per minute . at this rate , how many bottles could 10 such machines produce in 4 minutes ? 
Options: a ) 648 , b ) 1800 , c ) 2600 , d ) 10800 , e ) 10900

A:
c
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