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# In a classroom with 6 girls, the average height is x centimeters. If

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In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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11 Mar 2018, 20:04
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15% (low)

Question Stats:

89% (01:05) correct 11% (01:11) wrong based on 64 sessions

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In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

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Re: In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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11 Mar 2018, 23:16
Bunuel wrote:
In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

6girls avg = x

total sum = 6x

now $$\frac{6x+ J}{7}$$ = x-1

7x-7 = 6x+j

J= x-7
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Re: In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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12 Mar 2018, 00:32
Bunuel wrote:
In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

There are 7 girls in the classroom with the inclusion of Jenelle, and the average
height of the class was x centimeters when Jenelle was not there.

Now, Jenelle would have to be 7 centimeters less than the class average
if the new average height of the class is x-1 centimeters.

Therefore, Jennele's height is x-7(Option D)
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Re: In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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12 Mar 2018, 10:33
Bunuel wrote:
In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

$$6x + j = 7( x - 1)$$

Or, $$6x + j = 7x - 7$$

Or, $$j = x - 7$$ , Answer will be (D)
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In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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12 Mar 2018, 15:25
Given $$\frac{S}{6}$$ = x centimeters-> $$S = 6x$$

$$\frac{Jenelle + S}{6 + 1} = x - 1$$ -> $$J + S = 7x - 7$$

Substitute $$S = 6x$$ into second equation and you are left with $$J + 6x = 7x - 7$$. Simply for J and you left with $$J = x - 7$$.

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Re: In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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13 Mar 2018, 16:02
Bunuel wrote:
In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

The sum of the height of 6 girls is 6x. When Jenelle joins we have:

(6x + J)/7 = x - 1

6x + J = 7x - 7

J = x - 7

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In a classroom with 6 girls, the average height is x centimeters....  [#permalink]

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26 Jul 2018, 08:30
In a classroom with 6 girls, the average height is x centimeters

=> Sum of the heights of 6 girls = 6x

Let j be the height of Janelle

After Jenelle joins the class, the average height will be x−1

Sum of height of 6 girls + height of Janelle = Total number of girls * average height

=> 6x + j = 7 * (x - 1)

=> 6x + j = 7x - 7

=> j = x - 7

Hence option D
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Re: In a classroom with 6 girls, the average height is x centimeters. If  [#permalink]

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26 Jul 2018, 10:09
Bunuel wrote:
In a classroom with 6 girls, the average height is x centimeters. If Jenelle joins the class, the average height will be x−1 centimeters. How tall, in centimeters, is Jenelle?

A. x
B. x − 1
C. x − 6
D. x − 7
E. x − 8

(Total Age of 6 Girls + Jenelle) - Total Age of 6 Girls = Age of Jenelle

So, 7(x -1) - 6x = Age of Jenelle

Thus, 7x - 7 - 6x = Age of Jenelle

Or, x - 7 = Age of Jenelle , Answer must be (D)
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

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Re: In a classroom with 6 girls, the average height is x centimeters. If &nbs [#permalink] 26 Jul 2018, 10:09
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