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If a + b + c = 50, what is the value of a ?

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If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 22 Feb 2018, 21:08
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

92% (00:51) correct 8% (01:30) wrong based on 105 sessions

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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 22 Feb 2018, 21:37
1. c = 4a-6 , this does not give any information about exact numbers. Insufficient.

2. Average of b+c = 2a , which means b+c = 4a. But we do not have necessary information to calculate exact values. Insufficient. option 2

Now consider option 1 and 2 together , we can derive the value of a =10.

Ans: Option C
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 22 Feb 2018, 22:41
Bunuel wrote:
If a + b + c = 50, what is the value of a ?

(1) c = 4a - 6

(2) The average of b and c is 2a.


Statement 1
c = 4a - 6, substituting this in original equation we get:
a + b + 4a - 6 = 50 or 5a + b = 56.
But until we know the value of b, we cannot find 'a'. So not sufficient.

Statement 2
Given, (b+c)/2 = 2a or b+c = 4a. Substituing this in original equation we get:
a + 4a = 50 or 5a = 50 or a=10. This is sufficient.

Hence B answer
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 23 Feb 2018, 00:16
1
Bunuel wrote:
If a + b + c = 50, what is the value of a ?

(1) c = 4a - 6

(2) The average of b and c is 2a.



1) C=4A-6 but there is no info about b insufficient

2) b+c/2 = 2a b+c = 4a

a+b+c = 50 substitute above value 5a=50 a =10

(B) imo
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 23 Feb 2018, 00:17
akadiyan wrote:

2. Average of b+c = 2a , which means b+c = 4a.

Ans: Option C



now we know b+c = 4a

we have a+b+c=50
now substitute in the above value
a+4a = 50

a= 10

(B)
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 12 Mar 2018, 06:53
Hi Bunuel

Answer here is shwn as D. How can one proceed to find the value of a with Statement 1 only?

Thanks
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 12 Mar 2018, 07:15
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Re: If a + b + c = 50, what is the value of a ?  [#permalink]

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New post 12 Mar 2018, 08:48
akadiyan wrote:
1. c = 4a-6 , this does not give any information about exact numbers. Insufficient.

2. Average of b+c = 2a , which means b+c = 4a. But we do not have necessary information to calculate exact values. Insufficient. option 2

Now consider option 1 and 2 together , we can derive the value of a =10.

Ans: Option C



Average of b+c = 2a , which means b+c = 4a.

Replace b+c = 4a in the given equation and you will get

a + 4a = 50

a = 10

Sufficient (B)
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Re: If a + b + c = 50, what is the value of a ?   [#permalink] 12 Mar 2018, 08:48
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