Delhi Police Constable Exam Model Paper 4

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.
$2\left(\mathit{x}+5\right)=\mathit{x}+25$
Hence we get,
$2\mathit{x}+10=\mathit{x}+25\mathit{x}=25-10$
Hence, the daughter is 15 years old.