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A group of 7 boys are playing a game, 3 of the boys averaged scores of

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A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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10 May 2017, 02:25
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15% (low)

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82% (00:49) correct 18% (00:43) wrong based on 63 sessions

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A group of 7 boys are playing a game, 3 of the boys averaged scores of x points. The other 4 boys averaged scores of y points. Which of the following represents the average (arithmetic mean) score of all the boys?

A. 7/(3x + 4y)

B. (x + y)/7

C. (3x + 4y)/(7xy)

D. (3x + 4y)/7

E. 7x/(x + y)

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Re: A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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10 May 2017, 03:29
2
Total points of 1st group: 3x
Total points of 2nd group: 4y
Combined value of points: 3x+4y
Now, Average= Total value/Total candidates i.e $$\frac{(3x+4y)}{7}$$
Hence, Option D should be the correct answer.

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Re: A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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10 May 2017, 09:51
absolute sitter..
(3x + 4y)/7

option D
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A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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11 May 2017, 10:15
Bunuel wrote:
A group of 7 boys are playing a game, 3 of the boys averaged scores of x points. The other 4 boys averaged scores of y points. Which of the following represents the average (arithmetic mean) score of all the boys?

A. 7/(3x + 4y)

B. (x + y)/7

C. (3x + 4y)/(7xy)

D. (3x + 4y)/7

E. 7x/(x + y)

I got D, but to check I plugged in numbers.

Chose x = 21 and y= 7

(Wanted total to be divisible by 7, and one variable to be weighted much more heavily than other.)

(3*21) + (4*7) = 91
91/7 = 13
Plugged x=21 and y=7 into D, got 13. Correct.
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Re: A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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12 May 2017, 04:52
Bunuel wrote:
A group of 7 boys are playing a game, 3 of the boys averaged scores of x points. The other 4 boys averaged scores of y points. Which of the following represents the average (arithmetic mean) score of all the boys?

A. 7/(3x + 4y)

B. (x + y)/7

C. (3x + 4y)/(7xy)

D. (3x + 4y)/7

E. 7x/(x + y)

3 boys averaged score of x points. So total score of 3 boys = 3x
4 boys averaged score of y points. So total score of 4 boys = 4y
Total no. of boys = 7

Average (Arithematic mean) score of all the boys = (3x+4y)/7

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Re: A group of 7 boys are playing a game, 3 of the boys averaged scores of  [#permalink]

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12 May 2017, 13:39
Bunuel wrote:
A group of 7 boys are playing a game, 3 of the boys averaged scores of x points. The other 4 boys averaged scores of y points. Which of the following represents the average (arithmetic mean) score of all the boys?

A. 7/(3x + 4y)

B. (x + y)/7

C. (3x + 4y)/(7xy)

D. (3x + 4y)/7

E. 7x/(x + y)

Recall that average = sum / quantity. Since the average of the 3 boys is x points, the sum of the points for the 3 boys is 3x. Similarly, since the average of the 4 boys is y points, their sum is 4y. In total, the 7 boys scored 3x + 4y points. Since there are 7 boys in total, we can create the following weighted average equation:

(3x + 4y)/7

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Re: A group of 7 boys are playing a game, 3 of the boys averaged scores of &nbs [#permalink] 12 May 2017, 13:39
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