Mother was three times the age of her daughter five years ago. After five years, Mother will be twice as old as her daughter. How old is the daughter today?

Let daughter's current age = d, mother's current age = m. Five years ago: m-5 = 3(d-5), so m-5 = 3d-15, giving m = 3d-10. After five years (from present): m+5 = 2(d+5), so m+5 = 2d+10, giving m = 2d+5. Equating: 3d-10 = 2d+5, so d = 15. Substituting back: m = 2(15)+5 = 35. Verifying: 5 years ago daughter was 10, mother was 30 (3× relationship correct). In 5 years daughter will be 20, mother will be 40 (2× relationship correct). Daughter is 15 years old today.