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'.
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Question: Problem: jacob is 39 years old . he is 3 times as old as his brother . how old will jacob be when he is twice as old ?
Options: a ) 63 , b ) 64 , c ) 65 , d ) 76 , e ) 67

Answer: c

Question: Problem: ( 51 + 52 + 53 + + 100 ) is equal to :
Options: a ) 2525 , b ) 2975 , c ) 3225 , d ) 3775 , e ) 3885

Answer: d

Question: Problem: the difference between a number and its two - fifth is 510 . what is 30 % of that number ?
Options: a ) 158 , b ) 200 , c ) 255 , d ) 400 , e ) 280

Answer:
c