The sum of the salaries of A and B is Rs. 2100. A spends 80% of his salary and B spends 70% of his salary. If their savings are in the proportion of 4 : 3, then what is the salary of A?

Solution(By Examveda Team)

Clearly, A and B save 20% and 30% of their respective salaries
Let the salaries of A and B be x and y respectively
Then,
$$\eqalign{ & {\text{ = }}\frac{{{\text{20}}\% {\text{ of }}x}}{{{\text{30}}\% {\text{ of }}y}} = \frac{4}{3} \cr & \Rightarrow \frac{x}{5} \times \frac{{10}}{{3y}} = \frac{4}{3} \cr & \Rightarrow \frac{x}{y} = 2 \cr & \Rightarrow x = 2y \cr & \therefore x + y = 2100 \cr & \Rightarrow 2y + y = 2100 \cr & \Rightarrow 3y = 2100 \cr & \Rightarrow y = 700 \cr & {\text{A's salary}} = x = 2y \cr & = {\text{Rs}}{\text{. }}\left( {2 \times 700} \right) \cr & = {\text{Rs}}{\text{. }}1400 \cr} $$