In this task, you need to provide the correct option for a given problem from the provided options.

[EX Q]: Problem: how many kilograms of pure water is to be added to 100 kilograms of a 30 % saline solution to make it a 10 % saline solution .
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500
[EX A]: b

[EX Q]: Problem: in a certain large company , the ratio of college graduates with a graduate degree to non - college graduates is 1 : 8 , and ratio of college graduates without a graduate degree to non - college graduates is 2 : 3 . if one picks a random college graduate at this large company , what is the probability w this college graduate has a graduate degree ?
Options: a ) 1 / 11 , b ) 1 / 12 , c ) 1 / 13 , d ) 3 / 19 , e ) 3 / 43
[EX A]: d

[EX Q]: Problem: in a class of 40 students , 10 did not opt for math . 15 did not opt for science and 2 did not opt for either . how many students of the class opted for both math and science ?
Options: a ) 13 , b ) 15 , c ) 7 , d ) 17 , e ) 18
[EX A]:
c