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18 Mar 2018, 01:57
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
64% (01:43) correct
36%
(01:40)
wrong
based on 244
sessions
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If \((ax)^{16}(by)^{12}(cxy)^{17}(dxy)^{11}>0\), and all the variables are non-zero numbers, which of the following must be true?
A. ab>0
B. ab<0
C. cd>0
D. cd<0
E. None of the above.
A. ab>0
B. ab<0
C. cd>0
D. cd<0
E. None of the above.
18 Mar 2018, 05:23
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Jamil1992Mehedi
Hi Bunuel, i am confused about the OA. Perhaps my provided ans is wrong. Please Would you share the right ans and difficulty level.
If \((ax)^{16}(by)^{12}(cxy)^{17}(dxy)^{11}>0\), and all the variables are non-zero numbers, which of the following must be true?
A. ab>0
B. ab<0
C. cd>0
D. cd<0
E. None of the above.
If \((ax)^{16}(by)^{12}(cxy)^{17}(dxy)^{11}>0\), and all the variables are non-zero numbers, which of the following must be true?
A. ab>0
B. ab<0
C. cd>0
D. cd<0
E. None of the above.
Hi,
The OA is flawed. What is the source?
Solution..
\(a^{16}*b^{12}*c^{17}*d^{11}*x^{16+17+11}*y^{12+17+11}>0........a^{16}*b^{12}*c^{17}*d^{11}*x^{44}*y^{40}>0\)..
Now a, b, x and y have even power.
Raised to even power, they would always be POSITIVE. BUT without power, each could be positive or negative. Therefore we cannot comment on their PRODUCT without powers.
So we cannot comment on ab....
Now all other terms with a,b,x and y are positive, so \(c^{17}*d^{11}\) also should be > 0..
Therefore cd>0..
Ans C..
