A mother and daughter differ in age by 20 years. Let, daughter's age be 'x' Hence, Mothers age is 'x + 20'Five years hence, Daughter's age will be 'x + 5'And mothers age will be 'x + 25' Five years hence daughter's age will be half her mother's age. 2(x+5)=x+25 Hence we get, 2x+10=x+25x=25−10 Hence, the daughter is 15 years old.