The sum of a mother’s and daughter’s ages is (66) years. After (6) years, the mother’s age will be (2) times the daughter’s age. What is the daughter’s present age?

Correct answer: (20) years

Let the mother’s present age be \(x\) years and the daughter’s present age be \(y\) years. Then \(x+y=66\). After 6 years, their ages will be \(x+6\) and \(y+6\), so \(x+6=2(y+6)\). This gives \(x=2y+6\). Substituting in the first equation, \(2y+6+y=66\), so \(3y=60\) and \(y=20\). Therefore, the daughter’s present age is 20 years, making option B correct. Exam tip: In age problems, add the same number of years to both present ages when forming a future-age equation.