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'.

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
c

Problem: if a * b * c = ( √ ( a + 2 ) ( b + 3 ) ) / ( c + 1 ) , find the value of 6 * 15 * 2 . 
Options: a ) 8 , b ) 5 , c ) 11 , d ) 3 , e ) 4
e

Problem: find the mean proportional between 25 & 36 ? 
Options: a ) a ) 59 , b ) b ) 30 , c ) c ) 63 , d ) d ) 65 , e ) e ) 67

b