If 50% of (p - q) = 30% of (p + q), then p : q is equal to?

$$\eqalign{ & 50\% {\text{ of }}\left( {p - q} \right) = 30\% {\text{ of }}\left( {p + q} \right) \cr & \frac{{p - q}}{2} = \frac{3}{{10}}\left( {p + q} \right) \cr & \left[ {50\% = \frac{1}{2}} \right] \cr & \Rightarrow 5\left( {p - q} \right) = 3\left( {p + q} \right) \cr & \Rightarrow 5p - 5q = 3p + 3q \cr & \Rightarrow 2p = 8q \cr & \Rightarrow 1p = 4q \cr & \Rightarrow p:q = 4:1 \cr} $$