instruction:
In this task, you need to provide the correct option for a given problem on probability from the provided options.
question:
Problem: a jar contains 5 black and 2 white balls . if you pick two balls at the same time , what ' s the probability that one ball is black and one is white ? 
Options: a ) 2 / 7 , b ) 5 / 21 , c ) 4 / 21 , d ) 3 / 7 , e ) 1 / 2
answer:
b


question:
Problem: there are 7 pairs of socks and 2 socks are worn from that such that the pair of socks worn are not of the same pair . what is the number of pair that can be formed . 
Options: a ) 40 , b ) 49 , c ) 41 , d ) 56 , e ) 42
answer:
e


question:
Problem: from a group of 4 boys and 4 girls , 4 children are to be randomly selected . what is the probability that 2 boys and 2 girls will be selected ? 
Options: a ) 12 / 29 , b ) 14 / 31 , c ) 16 / 33 , d ) 18 / 35 , e ) 20 / 37
answer:

d