The salaries of Vipin and Dinesh are in the ratio 5 : 8. If the salary of each is increased by 4,800, then new ratio becomes 7 : 10. What is Vipin's salary?

Answer: Option A

Let the salary of Vipin and Dinesh be 5$$x$$ and 8$$x$$
$$\begin{array}{rl}& \frac{5x+4800}{8x+4800}=\frac{7}{10}\\ & \Rightarrow 50x+48000=56x+33600\\ & \Rightarrow x=\frac{14400}{6}\\ & \Rightarrow x=2400\end{array}$$
∴ Vipin's salary is Rs. 12000