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exponents

by thephoenix » Wed Feb 10, 2010 3:34 am
Is (4^x )^(5-3x)=1?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
Last edited by thephoenix on Wed Feb 10, 2010 5:11 am, edited 1 time in total.
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Source: — Data Sufficiency |
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by papgust » Wed Feb 10, 2010 3:42 am
thephoenix wrote:Is (4^x )^(5-3x)?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
The question doesn't seem complete to me. Have you checked the question properly?
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by thephoenix » Wed Feb 10, 2010 5:12 am
papgust wrote:
thephoenix wrote:Is (4^x )^(5-3x)?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
The question doesn't seem complete to me. Have you checked the question properly?
edited thanks for pointing
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by ajith » Wed Feb 10, 2010 9:41 am
thephoenix wrote:Is (4^x )^(5-3x)=1?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
(4^x )^(5-3x)
= 4^(x (5-3x))

for this to be 1

x (5-3x) = 0

either x =0 or x = 5/3

1) x is an integer is not sufficient
2) x is not zero is also not sufficient

Combined sufficient to conclude that x is neither zero nor 5/3 and hence (4^x )^(5-3x) not equal to 1
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by thephoenix » Wed Feb 10, 2010 9:58 am
ajith wrote:
thephoenix wrote:Is (4^x )^(5-3x)=1?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
(4^x )^(5-3x)
= 4^(x (5-3x))

for this to be 1

x (5-3x) = 0

either x =0 or x = 5/3

1) x is an integer is not sufficient
2) x is not zero is also not sufficient

Combined sufficient to conclude that x is neither zero nor 5/3 and hence (4^x )^(5-3x) not equal to 1
[spoiler]C (so good to see you back, thephoenix)
[/spoiler]
hey ajith thnks many a times i miss to solve together
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by sanju09 » Wed Feb 10, 2010 11:50 pm
thephoenix wrote:Is (4^x )^(5-3x)=1?
(1) x is an integer.
(2) The product of x and positive integer y is not x.

i dont have OA for this one
after solving i found E as the ans
i am posting this one here just to confirm my ans
help
I have reduced the question to

Is x 0 or 5/3?

(1) x is an integer.

(2) The product of x and positive integer y is not x.

(1) means that x is not 5/3, but it still may or may not be 0. Insufficient

(2) means that y is a positive integer greater than 1 and that x is not 0. It still may or may not be 5/3. Insufficient

Taken together makes us note that x is neither 0 nor 5/3, a definite NO to a YES/NO question. Sufficient

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by Mom4MBA » Fri Feb 12, 2010 12:45 pm
Is x 0 or 5/3?

(1) x is an integer.

(2) The product of x and positive integer y is not x.
I have a question here, when it is given in the statement 1 that x is an integer doesn't this mean that x will never be equal to 0 or 5/3 thus giving us a definite NO for our answer. I think statement 1 should be sufficient.

If I am wrong then please someone explain me how we getting a NO after combining the statements.

Thank you.
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by ajith » Fri Feb 12, 2010 2:01 pm
Mom4MBA wrote:
Is x 0 or 5/3?

(1) x is an integer.

(2) The product of x and positive integer y is not x.
I have a question here, when it is given in the statement 1 that x is an integer doesn't this mean that x will never be equal to 0 or 5/3 thus giving us a definite NO for our answer. I think statement 1 should be sufficient.

Zero is an integer (it is neither positive nor negative, nevertheless an integer)

If I am wrong then please someone explain me how we getting a NO after combining the statements.

Thank you.
The original Question was whether (4^x )^(5-3x)=1?
if (4^x )^(5-3x)=1; x =0 or 5/3

1) x is an integer - is not sufficient to conclude that (4^x )^(5-3x) is not equal to one (x can be 0 and that is only case when despite x being an integer (4^x )^(5-3x) is equal to 1)

2) x is not zero - is not sufficient to conclude that (4^x )^(5-3x) is not equal to one (x can be 5/3 and that is only case when (4^x )^(5-3x) is equal to 1)

Combining we can see that x is neither zero nor 5/3 , sufficient to conclude that (4^x )^(5-3x) is not equal to one

I think you did not look at the question as a whole and got confused
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by Mom4MBA » Fri Feb 12, 2010 2:09 pm
Ajith 0 is not an integer right it is a whole number........... so (4^x )^(5-3x)=1 can only be true is x=0 or 5/3 when statement 1 says that x is an integer that means it is neither 0 nor 5/3 hence sufficient.

Do I still sound confused.
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by Mom4MBA » Fri Feb 12, 2010 2:11 pm
I am so sorry again, I think I need to brush up my basics ................
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by ajith » Fri Feb 12, 2010 2:13 pm
Mom4MBA wrote:Ajith 0 is not an integer right it is a whole number........... so (4^x )^(5-3x)=1 can only be true is x=0 or 5/3 when statement 1 says that x is an integer that means it is neither 0 nor 5/3 hence sufficient.

Do I still sound confused.
Zero is an integer and a whole number (https://en.wikipedia.org/wiki/Integer)
https://en.wikipedia.org/wiki/Zero

Hope that helps
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