What quantity must be added to each term of the ratio x : y so that it may become equal to c : d ?
What must be added to each term of the ratio 2 : 3, so that it may become equal to 4:5?
What quantity must be added to each term of the ratio 6:11 so that it becomes equal to 2:3?
What quantity must be added to each term of the ratio 7:13 so as to make it equal to 9:11