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15 Jul 2018, 07:40
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A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
57% (01:45) correct
43%
(02:12)
wrong
based on 145
sessions
History
Date
Time
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Not Attempted Yet
What is the value of \(\frac{(8a + a - b)}{(a - b)}\) ?
(1) \(\frac{(5a + 4b)}{(a - b)} = 2\)
(2) \(a - b = 9\)
Source: GmatFree
(1) \(\frac{(5a + 4b)}{(a - b)} = 2\)
(2) \(a - b = 9\)
Source: GmatFree
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
15 Jul 2018, 08:25
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(8a+a−b) / (a−b)
(9a-b) /(a-b) Dividing both numerator and denominator by b, we get:
(9a/b - 1) / (a/b-1) ----> (A)
(1) (5a+4b) / (a−b)=2 (solving, we get)
3a-2b = 0
3a = 2b
a/b = 2/3
Now, putting the value of a/b in equation A the final value can be obtained, Sufficient.
(2) a−b = 9
putting b = a+9 in equation A we get 8a + 9 (not solvable), Insufficient
Hence, A.
(9a-b) /(a-b) Dividing both numerator and denominator by b, we get:
(9a/b - 1) / (a/b-1) ----> (A)
(1) (5a+4b) / (a−b)=2 (solving, we get)
3a-2b = 0
3a = 2b
a/b = 2/3
Now, putting the value of a/b in equation A the final value can be obtained, Sufficient.
(2) a−b = 9
putting b = a+9 in equation A we get 8a + 9 (not solvable), Insufficient
Hence, A.
15 Jul 2018, 08:40
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OA: A
\(\frac{(8a+a−b)}{(a−b)}\) can be simplified as \(\frac{8a}{a-b}+1\)
\(\frac{8a}{a-b}+1\) = \(\frac{8}{(1- \frac{b}{a})}+1\)
So we have to find value of \(\frac{b}{a}\)
1) \(\frac{(5a+4b)}{(a−b)}=2\)
if we take \(a=0\) ,\(L.H.S\neq{R.H.S}\), so it means \(a\neq{0}\)
Dividing numerator and denominator of \(L.H.S\) by \(a\) , we get
\(\frac{(5+4*\frac{b}{a})}{(1−\frac{b}{a})}=2\)
Solving above equation , we can find value of \(\frac{b}{a}\)
So Statement 1 alone is sufficient.
2) \(a−b = 9\)
Putting \(a-b\) in \(\frac{8a}{a-b}+1\) , we get \(\frac{8a}{9}+1\)
We still need value of \(a\).
So Statement 2 alone is not sufficient.
\(\frac{(8a+a−b)}{(a−b)}\) can be simplified as \(\frac{8a}{a-b}+1\)
\(\frac{8a}{a-b}+1\) = \(\frac{8}{(1- \frac{b}{a})}+1\)
So we have to find value of \(\frac{b}{a}\)
1) \(\frac{(5a+4b)}{(a−b)}=2\)
if we take \(a=0\) ,\(L.H.S\neq{R.H.S}\), so it means \(a\neq{0}\)
Dividing numerator and denominator of \(L.H.S\) by \(a\) , we get
\(\frac{(5+4*\frac{b}{a})}{(1−\frac{b}{a})}=2\)
Solving above equation , we can find value of \(\frac{b}{a}\)
So Statement 1 alone is sufficient.
2) \(a−b = 9\)
Putting \(a-b\) in \(\frac{8a}{a-b}+1\) , we get \(\frac{8a}{9}+1\)
We still need value of \(a\).
So Statement 2 alone is not sufficient.
