omar has $84 and Calina has $12. How much money must Omar give to Calina so that Calina would have three times as much as Omar?

Question

use let staments.

Answer 1

When possible, assign variables to the values the question asks you to find:

   Let x = amount Omar gives Calina

 

Translate:

  "Omar give to Calina so that Calina would have three times as much as Omar?"   and

      "omar has $84 and Calina has $12"                means

      3 *  ( $84 - x )       =              $12         +    x

 

       252  - 3x  = 12 + x             [distribute]

            - 4x  = -240              [subtract 252; subtract x from both sides]

                x = 60               [divide both sides by (-4)]

 

Check:

    Is  3(84-60) = 12 + 60   ?

         3(24) = 72   ?

           72 = 72   >yes

Answer 2

First, figure out how much total money there is:

 

84 + 12 = 96

 

Therefore we know that O + C = 96

 

We know that we want Calina to have 3 times as much as Omar, so the following equation must be true:

 

C = 3*O

 

Using substitution, the first equation becomes this:

 

O + 3*O = 96

4*O = 96

O = 96/4

O = 24

 

Therefore Omar must have $24 at the end of giving his money to Calina.

 

He currently has $84, so he must give 84-24 = $60.