after 12 years i shall be 3 times as old i was 4 years ago find my preasent age

Question

find the x

Answer 1

When convenient, assign a variable to the value the problem asks you to find (so you don't forget to solve for it at the end of your solution):

 

  Let x = your current age

 

Translate:

  "after 12 years i shall be 3 times as old i was 4 years ago"

        (x+12)          =        3   *                 (x-4)

 

The math:

 x+12 = 3(x-4)

 x + 12 = 3x - 12             [distribute]

  12 = 2x - 12                 [subtract x from both sides]

  24 = 2x                   [add 12 to both sides]

   12 = x                [divide both sides by 2]

 

Your current age is 12.

 

Check:

  Is   (12+12) = 3(12-4)   ?

            24    = 3(8)   ?

             24  =  24   ?yes

Answer 2

Letting x = present age

 

x + 12  will be my age 12 years from now.

3(x-4)  will be three times as old as I was 4 years ago

 

x+12 = 3(x-4)

Solve for x

 

x+12 = 3x - 12

subtract x from both sides

12 = 2x - 12

add 12 to both sides

24 = 2x

divide both sides by 2

12 = x

 

My present age is 12 years

 

Check:  x+12 = 3(x-4)

          12+12 = 3(12-4)

             24 = 3(8)

             24 = 24

This balances and answer is correct