Salaries of two persons A and B are in the ratio 2: 3. If A spent 40% of the salary on rent and B spent 30% of the salaries on rent. If the remaining amount of A and B are Rs. 3x and Rs. (5x + 500.Then A spends 1/3rd of the remaining salary on groceries and B spends 1/5th of the remaining amount on groceries. The remaining salary of both persons A and B is Rs. 12400. Find the difference between the initial salary of person A and x.