Ankit is three times as old as his sister, and his mother is 8 times as old as his sister. 10 years hence, Ankit’s mother will be twice his age. How old will Ankit’s mother be when she is 6 times the age of her daughter?

Let sister's current age be x. Ankit=3x, Mother=8x. In 10 years: 8x+10=2(3x+10). Solving: 8x+10=6x+20, so 2x=10, x=5. Current ages: sister=5, Ankit=15, Mother=40. When mother is 6× daughter's age: let daughter be d, mother=6d. Their age difference is always 35, so 6d-d=35, 5d=35, d=7. At that time, mother=42. Answer claims 42 years, which matches.