Question 1042637
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if the total cost of x apples is b cents, what is a general formula for the cost, in cents, of y apples?
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<pre>
1.  If "x" apples cost b cents, then one apple costs {{{b/x}}} cents.

    Agree?

    Now, if one apple costs {{{b/x}}} cents, then "y" apples cost {{{(b*y)/x}}} cents.

    Did you get it?


2.  Proportions.

    If "z" is the cost of "y" apples, then you have this proportion

    {{{b/x}}} = {{{z/y}}}.

    Each side is the price of one single apple.

    In proportion, a mean term is the product of the two extreme terms divided  by the other mean term. 

    It gives you

    z = {{{(b*y)/x}}}.

    Exactly the same as in the first approach.
</pre>

On proportions, see the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/proportions/lessons/-Proprtions.lesson>Proportions</A>

in this site.


You have also this free of charge online text-book in Algebra-I

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>

in this site.