Sonam’s age after eight years will be half of her father’s age. Eight years ago the ratio of their ages was 1 : 3. Find the present age of Sonam's father?

Let Sonam be S and her father F. Eight years ago (S − 8)/(F − 8) = 1/3, so F = 3S − 16. After eight years S + 8 = (F + 8)/2, so F = 2S + 8. Equating: 3S − 16 = 2S + 8, giving S = 24 and F = 56.