Question 969119
<pre>
Let the number of hot dogs be x.
Then the number of sodas, using
ONE PART = TOTAL MINUS OTHER PART,
is 87-x.
                      Money      Money
          Number      from       from
           sold       EACH        ALL
-------------------------------------------
hot dogs     x        $1.50     $1.50x
sodas      87-x       $0.50     $0.50(87-x)
-------------------------------------------
TOTALS      87        -----    $78.50

 The equation comes from the column on the right

{{{(matrix(4,1,money,from,ALL,hot_dogs))}}}{{{""+""}}}{{{(matrix(4,1,Money,from,ALL,sodas))}}}{{{""=""}}}{{{(matrix(4,1,Total,money,taken,in))}}}

1.50x + 0.50(87-x) = 78.50

Get rid of decimals by multiplying every term by 100:

   150x + 50(87-x) = 7850

 150x + 4350 - 50x = 7850

       100x + 4350 = 7850

              100x = 3500

                 x = 35 = the number of hot dogs.

The number of sodas is 87-x or 87-35 or 52 sodas.

Checking:  35 hot dogs is $52.50 and 52 sodas is $26.00

            And indeed $52.50 + $26.00 = $78.50

Edwin</pre>