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: find the least number of 5 digits which is exactly divisible by 12 , 15 and 18 ? 
Options: a ) 1080 , b ) 10080 , c ) 10025 , d ) 11080 , e ) 12080
b

Problem: what is the average of first 21 multiples of 6 ? 
Options: a ) a ) 66 , b ) b ) 77 , c ) c ) 79 , d ) d ) 81 , e ) e ) 82
a

Problem: the average age of students of a class is 15.8 years . the average age of boys in the class is 16.4 years and that of the girls is 15.4 years , the ratio of the number of boys to the number of girls in the class is : 
Options: a ) 2 : 9 , b ) 2 : 3 , c ) 2 : 1 , d ) 2 : 2 , e ) 2 : 6

b