Question 1127512
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The algebraic solution method is fine.  But if a formal solution is not required, you can get the answer to this problem (and many similar problems) much faster and with less work using logical reasoning.<br>
For this problem, the reasoning goes like this:<br>
(1) If all 1600 items were small pizzas, the total sales would be 1600*$9 = $14,400.
(2) The actual sales amount was $15,600; the difference between the two totals is $15,600-$14,400 = $1200.
(3) Each pasta dinner costs $4 more than each small pizza.
(4) To make the additional $1200, the number of pasta dinners sold has to be $1200/$4 = 300.
(5) The number of small pizzas sold was 1600-300 = 1300.