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Question 7 (nov. 14th)

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Question 7 (nov. 14th)

by bacali » Fri Nov 14, 2008 1:15 pm
Each of the 30 boxes in a certain shipment with either 10 pounds or 20 pounds, and the average (arithmetic mean) weight of the boxes in the shipment is 18 pounds. If the average weight of the boxes in the shipment is to be reduced to 14 pounds by removing some of the 20-pound boxes, how many 20-pound boxes must be removed?



A. 4
B. 6
C. 10
D. 20
E. 24
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by dmateer25 » Fri Nov 14, 2008 1:25 pm
30 * 18 = 540 (total weight)


Let x= number of 20 pound boxes removed

14(30-x)=540-20x
420-14x=540-20x
6x=120
x=20

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by cramya » Fri Nov 14, 2008 1:25 pm
Once more vote for 20
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by bacali » Fri Nov 14, 2008 8:59 pm
OA : D
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