In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Q: Problem: pure milk costs 3.60 per litre . a milkman adds water to 25 litres of pure milk and sells the mixture at 3 per litre . how many litres of water does he add ? 
Options: a ) 2 litres , b ) 5 litres , c ) 7 litres , d ) 11 litres , e ) none of these

A: b
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Q: Problem: the sum of the first 50 positive even integers is 2550 . what is the sum w of even integers from 102 to 200 inclusive ? 
Options: a ) 5100 , b ) 7550 , c ) 10100 , d ) 15500 , e ) 20100

A: b
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Q: Problem: the smallest value of n , for which 2 n + 1 is not a prime number , is 
Options: a ) 3 , b ) 4 , c ) 5 , d ) none , e ) 6

A:
b
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