Question 731816
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Isabelle bought 12 wallet-sized photos for $36. Use a ratio table to determine how much she will pay for 5 more photos.

I drew the ratio table but cannot figure out what to do next. Please help me. Thanks!
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        I will provide two solutions.


        First solution is of the 5-th grade level student, who just solves problems on division and multiplication 

        of integer numbers, but does not know proportions yet.


        Second solution is of the level of the 6-th grade level student, who just learned proportions.


        You select the one of these two solutions, which suits better your needs and your level.



                      First solution of the 5-th grade level student


<pre>
12 photos cost &36 dollars - hence, one photo costs  36/12 = 3 dollars.

Then 5 more than 12 photos costs (12+5)*3 = 17*3 = 51 dollars.

It is your <U>ANSWER</U> :  51 dollars.
</pre>


      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Second solution of the 6-th grade level student


<pre>
Make a proportion

    {{{36/12}}} = {{{x/(12+7)}}},


where 'x' is what you want to get.


Simplify the proportion

    {{{36/12}}} = {{{x/17}}}.


Now from the proportion find  x = {{{(36*17)/12}}} = 3*17 = 51  dollars.


It is the same value, as in my first solution above.
</pre>

Solved in two different ways for your better understanding.


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By the way, the meaning of the proportion is that the unit price for one photo is the same in both cases.