Rapid Revision for CSIR NET Part A: Formula Sheets on Problem On Age - Check Here!!!

By Astha Singh|Updated : January 25th, 2022

CSIR NET Part-A Formula Sheet: During the preparation, the candidates study different formulas to solve problems, but at the last moment, these formulas might not be remembered by the candidates due to exam fear or pressure. We at BYJU'S Exam Prep do not want our students to lag anywhere during the preparation, so we have come up with a concept of a Formula Sheet that will help them revise the important formulas at the last moment. This formula sheet will be a short revision tool and contain only important formulas that need to be studied at the last minute to boost the score. Our experienced subject-matter experts have meticulously designed this CSIR NET General Aptitude Formula Sheet to provide you with the best authentic material. 

In this article, we will cover the CSIR NET General Aptitude Most Important Formulas of Problem On Age. Aspiring candidates can check all the most important formulas of Problem On Age for the last minute revision. Scroll down the full article to find out!

Most Important Formulas of Problem On Age


 Points to be Remember when Solving Problems on Ages.

  • If the present age of a person is ‘x’, then the age after the ‘n’ year will be x + n.
  • If the present age of a person is ‘x’, then age ‘n’ years ago will be = x-n.
  • If the present age of the person is ‘x’, then ‘n’ times the present age will be = nx⦁
  • If the age is mentioned in the ratio A: B, then A: B will be AX and BX.
  • If the sum of ages is X and Y and the ratio of their ages in p: q, then you can determine the age of ‘Y’ by the formula below       

Age of Y=   sum of ages        

Age of Y=  A

Some of these examples will make it easy to understand problems on ages

1. The ratio of the ages of Ravi and Rohit is 9: 10 respectively. Ten years of age, the ratio of their ages was 4: 5 respectively. What is the present age of Rohit? 

A. 15 years

B. 18 years 

C. 20 years 

D. 22 years.

So, Let Ravi age be 9x years. Then Rohit age = 10x year 


 ∴ Present age of Rohit = (10. 2) = 20 years

2. The age of the father 10 years ago was thrice the age of his son. 10 years hence, the father’s age will be twice that of his son. The ratio of their present ages is 

A. 8: 5 

B. 7: 3 

C. 9: 5 

D. 5: 2

Sol. Let Son’s age 10 years ago be x years Then, Father’s age 10- years ago = 3x years 

Son’s age Now = (x + 10) years, 

Father’s age now = (3x + 10) years (3x + 10) + 10 = 2[(x + 10) + 10]  ⇒ 3x + 20 = 2(x + 20) ⇒ 3x + 20 = 2x + 40 ⇒ x = 20 

The ratio of present ages of Father and Son 

3. The ratio of the present age of a Mother and her Daughter is 7: 1. Four years ago, the ratio of their ages was 19: 1. What will be the Mother’s age four years from now? 

A. 46 years  

B. 42 years 

C. 38 years 

D. 36 years.

Let Mother’s age be 7x years.  Then Daughter’s age = x years  


Mother’s age after 4 years = (7x + 4) = (7  6 + 4) years = 46 years

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