If x : y = 7 : 3 then the value of xy + y^2x^2 - y^2 is?

Answer: Option A

$$\begin{array}{rl}& x:y\\ & 7:3\\ & \therefore \frac{xy+y^2}{x^2-y^2}\\ & =\frac{21+9}{49-9}\\ & =\frac{30}{40}\\ & =\frac{3}{4}\end{array}$$