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: how many integerskgreater than 100 and less than 1100 are there such that if the hundreds and the units digits ofkare reversed , the resulting integer is k + 99 ? 
Options: a ) 50 , b ) 60 , c ) 70 , d ) 80 , e ) 90
e

Problem: 1 , 6 , 16 , 31 , 51 , ( . . . . ) 
Options: a ) 61 , b ) 66 , c ) 76 , d ) 86 , e ) 83
b

Problem: in the youth summer village there are 300 people , 200 of them are not working , 100 of them have families and 125 of them like to sing in the shower . what is the largest possible number of people in the village , which are working , that do n ' t have families and that are singing in the shower ? 
Options: a ) 150 , b ) 125 , c ) 175 , d ) 200 , e ) 100

e