10 years ago, the daughter's age is 4 times the mother's age. After 8 years, mother's age will be twice the daughter's age. What is daughter's present age?

Let daughter's present age be d, mother's present age be m. 10 years ago: (d - 10) = 4(m - 10) → d - 10 = 4m - 40 → d = 4m - 30. After 8 years: (m + 8) = 2(d + 8) → m + 8 = 2d + 16 → m = 2d + 8. Substituting: d = 4(2d + 8) - 30 = 8d + 32 - 30 = 8d + 2. So -7d = 2, which is impossible. The correct setup: 10 years ago mother was 4× daughter: m-10 = 4(d-10). After 8 years: m+8 = 2(d+8). Solving: m = 4d - 30 and m = 2d + 8. Equating: 4d - 30 = 2d + 8 → 2d = 38 → d = 19.