The sum of the present ages of a father and his son is 52 years. Six years ago, father's age was four times the age of the son. After 6 years, son's age will be: Choose the correct answer.
A) 14 B) 16 C) 18 D) 20 E) 22
Let the present ages of son and father be x and (52 - x) years respectively.   Then, (52 - x) - 6 = 4(x - 6)   46 - x = 4x - 24   x = 14   The son's age after 6 years will be 20.   The answer is 20.
<result>D</result>
The sum of the present ages of a father and his son is 52 years. Six years ago, father's age was four times the age of the son. After 6 years, son's age will be: