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: the product of two numbers is 2028 and their h . c . f is 13 . the number of such pairs is : 
Options: a ) 1 , b ) 2 , c ) 3 , d ) 4 , e ) 5
b

Problem: a city with a population of 126,160 is to be divided into 7 voting districts , and no district is to have a population that is more than 10 percent greater than the population of any other district . what is the minimum possible population that the least populated district could have ? 
Options: a ) 16,500 , b ) 16,600 , c ) 16,700 , d ) 16,800 , e ) 16,900
b

Problem: the average age of a class of 20 students is 19 years . the average increased by 2 when the teacher ' s age also included . what is the age of the teacher ? 
Options: a ) 40 years , b ) 41 years , c ) 42 years , d ) 43 years , e ) 44 years

b