If x:y = 1:2 and y:z = 3:4, find the ratio of $(x+y) : (y+z)$.

y को समान करें। x:y = 3:6, y:z = 6:8। तो x:y:z = 3:6:8। (x+y):(y+z) = (3+6):(6+8) = 9:14।