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: a student chose a number , multiplied it by 8 , then subtracted 138 from the result and got 102 . what was the number he chose ? 
Options: a ) 30 , b ) 120 , c ) 130 , d ) 140 , e ) 150
a

Problem: a corporation that had $ 115.19 billion in profits for the year paid out $ 230.10 million in employee benefits . approximately what percent of the profits were the employee benefits ? ( note : 1 billion = 10 ^ 9 ) 
Options: a ) 50 % , b ) 20 % , c ) 5 % , d ) 2 % , e ) 0.2 %
e

Problem: in a group of ducks and cows , the total number of legs are 34 more than twice the no . of heads . find the total no . of buffaloes . 
Options: a ) 11 , b ) 12 , c ) 14 , d ) 17 , e ) 18

d