If x:y=9:4 then (7x-3y) : (7x+3y)=?	Select the correct option
A) 51:76  B) 6:13  C) 51:75  D) 51:76  E) None of these
Explanation:   x/y = 9/4 (Given)   (7x − 3y)/(7x + 3y)   7(x/y) − 3/7(x/y)+3   ( on dividing Nr and Dr by y)   (7(9/4) − 3)/(7(9/4) + 3)   (63/4 − 3/1)/(63/4 + 3/1)   [(63 − 12)/4]/[(63 + 12)/4] = 51/75   (7x-3y) : (7x+3y) = 51:75   Answer: Option 51:75
<result>C</result>
If x:y=9:4 then (7x-3y) : (7x+3y)=?