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'.

[EX Q]: Problem: ages of two persons differ by 20 years . if 6 year ago , the elder one be 3 times as old the younger one , find their present age 
Options: a ) 12,28 , b ) 14,30 , c ) 16,36 , d ) 18,34 , e ) 19,34
[EX A]: c

[EX Q]: Problem: the mean of 40 observations was 100 . it was found later that an observation 50 was wrongly taken as 75 the corrected new mean is 
Options: a ) 125.8 , b ) 102.8 , c ) 99.375 , d ) 100.52 , e ) 122
[EX A]: c

[EX Q]: Problem: a cyclist rides a bicycle 9 km at an average speed of 12 km / hr and again travels 12 km at an average speed of 9 km / hr . what is the average speed for the entire trip ? 
Options: a ) 9.5 , b ) 9.8 , c ) 10.1 , d ) 10.6 , e ) 11.2
[EX A]:
c