Q. 383.9( 14 Votes )

One year ago, a man was 8 times as old as his son. Now, his age is equal to the square of his son's age. Find their present ages.

Answer :

Let the present age of son be x years

The present age of man = x2 years


One year ago age of son = (x – 1)years


age of man = (x2 – 1)years


According to given question, One year ago, a man was 8 times as old as his son

x2 – 1 = 8(x – 1)

x2 – 1 = 8x – 8

x2 – 8x + 7 = 0

x2 – 7x – x + 7 = 0

x(x – 7) – 1(x – 7) = 0

(x – 7) (x – 1) = 0

x = 1 or x = 7

Man’s age cannot be 1 year

Thus x = 7

Thus the present age of son is 7 years

The present age of man is 72 = 49 years

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Get To Know About Quadratic Formula42 mins
Quiz | Knowing the Nature of Roots44 mins
Take a Dip Into Quadratic graphs32 mins
Foundation | Practice Important Questions for Foundation54 mins
Nature of Roots of Quadratic Equations51 mins
Getting Familiar with Nature of Roots of Quadratic Equations51 mins
Quadratic Equation: Previous Year NTSE Questions32 mins
Champ Quiz | Quadratic Equation33 mins
Understand The Concept of Quadratic Equation45 mins
Balance the Chemical Equations49 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses