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

Q: Problem: bag a contains red , white and blue marbles such that the red to white marble ratio is 1 : 3 and the white to blue marble ratio is 2 : 3 . bag b contains red and white marbles in the ratio of 1 : 4 . together , the two bags contain 40 white marbles . how many red marbles could be in bag a ? 
Options: a ) 8 , b ) 3 , c ) 4 , d ) 6 , e ) 8

A: a
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Q: Problem: a certain business school has 500 students , and the law school at the same university has 800 students . among these students , there are 30 sibling pairs consisting of 1 business student and 1 law student . if 1 student is selected at random from both schools , what is the probability that a sibling pair is selected ? 
Options: a ) 3 / 40000 , b ) 3 / 20000 , c ) 3 / 4000 , d ) 9 / 400 , e ) 6 / 130

A: a
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Q: Problem: the compound ratio of 5 : 6 , 3 : 2 and 6 : 5 ? 
Options: a ) 1 : 1 , b ) 1 : 87 , c ) 1 : 6 , d ) 3 : 2 , e ) 1 : 2

A:
d
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