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: if one root of the equation 2 x ^ 2 + 3 x – k = 0 is 5 , what is the value of k ? 
Options: a ) 65 , b ) 79 , c ) 68 , d ) 87 , e ) 90

A: a
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Q: Problem: s ( n ) is a n - digit number formed by attaching the first n perfect squares , in order , into one integer . for example , s ( 1 ) = 1 , s ( 2 ) = 14 , s ( 3 ) = 149 , s ( 4 ) = 14916 , s ( 5 ) = 1491625 , etc . how many digits r are in s ( 99 ) ? 
Options: a ) r = 350 , b ) r = 353 , c ) r = 354 , d ) r = 356 , e ) 357

A: b
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Q: Problem: the average age of 15 students of a class is 15 years . out of these , the average age of 5 students is 12 years and that of the other 9 students is 16 years . the age of the 15 th student is ? 
Options: a ) 11 years , b ) 17 years , c ) 21 years , d ) 14 years , e ) 12 years

A:
c
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