Number System
The peresent age of the father and the son are in the ratio of 8:3. After 12 years the ratio of their ages will be 2:1. What is the sum of the present age of the father and the son ?
Let the present age of the father be 'x' and that of the son be 'y'. Then x/y = 8/3∴ 3x = 8y Further, x + 12/y + 12 = 2/1 ∴ x + 12 = 2y + 24 ∴ x - 2y = 12 ......(ii)From eqn (i) and (ii), x = 48, y = 18 ∴ sum = 66 yrs.
Since the number is greater than the number obtained on reversing the digits, so the ten's digit is greater than the unit's digit.Let the ten's and unit's digits be 2x and x respectively.Then, (10 * 2x + x) - (10x + 2x) = 369x = 36x = 4Required difference = (2x + x) - (2x - x) = 2x = 8.