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

[EX Q]: Problem: if the ratio of a to b is 7 to 3 and the ratio of b to c is 1 to 5 , what is the ratio of a to c ? 
Options: a ) 4 / 15 , b ) 1 / 3 , c ) 2 / 5 , d ) 4 / 5 , e ) 7 / 15
[EX A]: e

[EX Q]: Problem: in a bag , there are 2400 ball , and their colors are red , green blue . . the ratio of the balls are 15 : 13 : 17 . then how many red color balls are available in the bag ? 
Options: a ) 900 , b ) 1600 , c ) 750 , d ) 890 , e ) 1010
[EX A]: a

[EX Q]: Problem: in a college , the ratio of the number of boys to girls is 8 : 5 . if there are 400 girls , the total number of students in the college is 
Options: a ) 1040 , b ) 920 , c ) 980 , d ) 720 , e ) 820
[EX A]:
a