Four years ago, the ratio of ages of a brother and

Solution

Four years ago,   let the age of the brother = 5x years. Then, the age of the sister = 5x × (6/5) = 6x years. Present age of the brother = (5x + 4) years. Present age of the sister = 47 - (5x + 4) = (43 - 5x) years. 3 years hence, age of the sister = 6x + 4 + 3 = (6x + 7) years, age of the brother = (43 - 5x + 3) = (46 - 5x) years.   According to the question,   2 × (46 - 5x) = 6x + 7. 92-10x =6x+7 16x =85 Solving, we get x = 5.3 Thus, the current age of the brother = 5x + 4 =5 ×5.3+4= 30.5 years.