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'.

[EX Q]: Problem: if ( 1 1.5 ) n = 1 , then n =
Options: a ) 400 , b ) 140 , c ) 2 , d ) 4 , e ) 400
[EX A]: c

[EX Q]: Problem: each of the products produced yesterday was checked by worker x or worker y . 0.5 % of the products checked by worker x are defective and 0.8 % of the products checked by worker y are defective . if the total defective rate of all the products checked by worker x and worker y is 0.7 % , what fraction of the products was checked by worker y ?
Options: a ) 2 / 3 , b ) 5 / 6 , c ) 7 / 8 , d ) 4 / 5 , e ) 5 / 8
[EX A]: a

[EX Q]: Problem: how many two - element subsets of { 1,2 , 3,4 } are there that do not contain the pair of elements 2 and 4 ?
Options: a ) one , b ) two , c ) four , d ) five , e ) six
[EX A]:
d