PLEASE explain this math question

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PLEASE explain this math question

by mostovari » Tue Dec 02, 2008 5:34 pm
The table below shows the total sales recorded in July for the 5 salespeople at a certain company. It was discovered that one of Cal's sales was incorrectly recorded as one of Ann's sales. After this error was corrected, Ann's total sales were still higher than Cal's total sales, and the median of 5 sales total was 330,000. What was the value of the incorrectly recorded sale?

Ann: 450,000 - Bob: 360,000 - Cal: 190,000 - Pat: 210,000 - Ed: 680,000.

A. 30,000
B. 48,000
C. 90,000
D. 120,000
E. 14,000
Source: — Problem Solving |

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by reneerenee » Tue Dec 02, 2008 5:53 pm
i thinkk its [b]D[/b]. subtract 120000 from Anns numbers and add it to Cal's numbers and you'll get the conditions that the problem asked for.

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by mostovari » Tue Dec 02, 2008 6:49 pm
Reneerenee - Could you please explain what you mean by (b)D(/b)? I still don't understand :( Thanks.

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by ljpmn79 » Wed Dec 03, 2008 8:05 am
We know that the median sales number will be 330,000. Since there is not any employee with that sales number, we know that either Ann or Cals adjusted numbers must change to 330,000, and that this number will be the median of the resulting totals.

If Cal's number changes to 330,000, that means the incorrectly recorded sale was for 140,000. (190,000 + 140,000 = 330,000). That means that Ann's new sale number is 450,000-140,000 = 310,000. We know this cannot be accurate because the question states that Ann's sales number, after it is adjusted, will still be more than Cal's.

Therefore, Ann's number must be the one to change to 330,000. That means that the incorrect sale was 120,000 (450,000-120,000 = 330,000).

The answer is D.