Question 134729
A grocer bought some boxes of apples for $70. However, 4 boxes were spoiled. The grocer sold the remaining boxes at a profit of $2. How many boxes did the grocer sell if she managed to break even?
:
Let x = no. of boxes he sold to break even
then
(x+4) = original number of boxes bought
:
Price paid for each box = {{{70/((x+4))}}}
:
The break-even equation:
x({{{70/((x+4)) + 2}}}) = 70
:
{{{(70x)/((x+4)) + (2x)}}} = 70
:
70x + 2x(x+4) = 70(x+4); multiplied equation to get rid of the denominator
:
70x + 2x^2 + 8x = 70x = 280
:
70x - 70x + 8x + 2x^2 - 280 = 0; combine like terms on the left
:
2x^2 + 8x - 280 = 0; a quadratic equation
:
x^2 + 4x - 140 = 0; simplified
:
(x+14)(x-10) = 0; factored
;
x = +10 boxes sold is our positive solution
:
:
See if that will work
Total boxes bought 14: Price paid: 70/14 = $5
Price sold: 5 + 2 = $7; 10 boxes sold = $70
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Hey, did all this make sense to you?