The income of A and B are in the ratio of 4:7. A and B saves Rs. 4000 and 5000 respectively. If the expenditure of A is equal to 60% of the expenditure of B. Then, find the difference between their incomes.

Let incomes be 4x and 7x for A and B respectively. Expenditure = Income - Savings. A's expenditure = 4x - 4000. B's expenditure = 7x - 5000. Given: A's expenditure = 0.6 × B's expenditure, so 4x - 4000 = 0.6(7x - 5000). Solving: 4x - 4000 = 4.2x - 3000, giving -1000 = 0.2x, so x = 5000. A's income = 20000, B's income = 35000. Difference = 35000 - 20000 = 15000.