Question

Five years hence, the age of jacob will be three times that of his son. Five years ago, Jacob`s age was seven times that of his son. What are their present ages?

Answer 1

Jacob 40 years nd son 10 years

Answer 2

$\huge\sf{\underline{\underline{Solution:}}}$

Given :-

• The age of Jacob will be three times that of his son.

• Five years ago, Jacob's age was seven times that of his son.

To find :-

• Their present ages.

Let the present age of Jacob be be x year                  

And the present Age of his son be be y year    

             

Five years Ago,

Jacob’s age will be = x + 5 year                  

Age of his son will be = y + 5 year      

           

According to the Question,

⇒ x + 5 = 3(y + 5)                  

Adding 5 to both side,                  

⇒ x = 3y + 15 - 5                  

⇒ x = 3y + 10 … (i)                  

Five years ago,                  

Jacob’s age= x - 5 year                  

His son’s age = y - 5 year                  

Jacob’s age was seven times that of his son                  

⇒ x - 5 = 7(y - 5)                  

Putting the value of x from equation (i) we get                  

⇒ 3y + 10 - 5 = 7y - 35                  

⇒ 3y + 5 = 7y – 35                  

⇒ 3y - 7y = - 35 - 5                  

⇒ -4y = - 40                  

⇒ y = - 40/-4                  

⇒ y = 10 year                  

Putting the value of y in equation we get                  

⇒ x = 3 × 10 + 10                  

⇒ x = 40 years        

         

Present age of Jacob = 40 years,

Present age of his son = 10 years.