temperature

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temperature

by rupsk » Fri Jul 29, 2011 8:20 pm
during a five day period, monday through friday, the average high temperature was 86 degree. wht was the temp on friday?
1. the avg high temperature for monday through thursday was 87 degree.
2 the high temp on friday reduced the avg high temp for the week by 1 degree.

I know 1 will give us solution. need an explanation for the 2.
Source: — Data Sufficiency |

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by mirantdon » Fri Jul 29, 2011 10:03 pm
+1 for D.
*For Statement 2 :
The temperature for friday = 86*6-87*5 (need not calculate)

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by jaymw » Sat Jul 30, 2011 1:33 am
rupsk wrote:during a five day period, monday through friday, the average high temperature was 86 degree. wht was the temp on friday?
1. the avg high temperature for monday through thursday was 87 degree.
2 the high temp on friday reduced the avg high temp for the week by 1 degree.

I know 1 will give us solution. need an explanation for the 2.
Let x be the high temperature on Friday.

Statement 1:


87*4+x=86*5

We can solve for x.

SUFFICIENT

Statement 2:


Same equation. We know that the avg. high temp is 86 degrees for the week. We also know that without the Friday, it would be 87 degrees for the first four days of the week.

SUFFICIENT
[spoiler]
Hence, D.[/spoiler]

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by GMATGuruNY » Sat Jul 30, 2011 2:41 am
rupsk wrote:during a five day period, monday through friday, the average high temperature was 86 degree. wht was the temp on friday?
1. the avg high temperature for monday through thursday was 87 degree.
2 the high temp on friday reduced the avg high temp for the week by 1 degree.

I know 1 will give us solution. need an explanation for the 2.
When given an average, determine the sum.
For 5 days with an average high temperature of 86, sum = 5*86 = 430.

Statement 1: The average high temperature for Monday through Thursday was 87 degrees.
For 4 days with an average high temperature of 87, sum = 4*87 = 348.
Thus, 5th day = 430-348 = 82.
Sufficient.

Statement 2: The high temperature on Friday reduced the average high temperature for the week by 1 degree.
Since the average high temperature for the week was 86, statement 2 indicates that the average high temperature Monday through Thursday was 1 degree higher (87 degrees).
Same information as given in statement 1.
Sufficient.

The correct answer is D.
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by rupsk » Sat Jul 30, 2011 4:52 am
thanks for the replies. but my questions are
1.Can we take week as five dya period?
2. If yes then how come reduced in one degree in avg equals to 87?