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

Problem: the sub - duplicate ratio of 9 : 25 is 
Options: a ) 4 : 3 , b ) 1 : 2 , c ) 3 : 5 , d ) 1 : 4 , e ) 2 : 3
c

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 26 white marbles . how many red marbles could be in bag a ? 
Options: a ) 1 , b ) 3 , c ) 4 , d ) 2 , e ) 8
d

Problem: the ratio between speed of the two trains is 7 : 8 . if the 2 nd train runs 400 km in 4 hrs , what is the speed of the 1 st train ? 
Options: a ) 87.9 , b ) 87.5 , c ) 87.7 , d ) 87.6 , e ) 43.3

b