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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
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VeritasPrepKarishma wrote:
aselfmademan wrote:
What is greatest positive integer n such that 2^n is a factor of 12^10?

a)10
b)12
c)16
d)20
e)60

Please show me the easy way to solve such question...


\(12^{10} = (2^2*3)^{10} = 2^{20}*3^{10}\)
The greatest value of n such that \(2^n\) is a factor of \(12^{10}\) is 20.

Such questions are more popular and a little more complex with factorials. e.g. What is greatest positive integer n such that \(2^n\) is a factor of 12!
Try this one.


Thank you very much.......... :-D I am very weak in this type of PS math :(
Could you please explain 12! math you have given ?
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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
VeritasPrepKarishma wrote:
aselfmademan wrote:
What is greatest positive integer n such that 2^n is a factor of 12^10?

a)10
b)12
c)16
d)20
e)60

Please show me the easy way to solve such question...


\(12^{10} = (2^2*3)^{10} = 2^{20}*3^{10}\)
The greatest value of n such that \(2^n\) is a factor of \(12^{10}\) is 20.

Such questions are more popular and a little more complex with factorials. e.g. What is greatest positive integer n such that \(2^n\) is a factor of 12!
Try this one.



n = 10

I just counted the number of 2s till 12 since the 12! is multiplication of all numbers till 12


Do you have any faster method which can be used for bigger factorials?
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What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
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Please check my signature for the link to the relevant blog posts.

Originally posted by KarishmaB on 27 Oct 2011, 20:39.
Last edited by KarishmaB on 11 Oct 2022, 00:49, edited 1 time in total.
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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
Expert Reply
aselfmademan wrote:
What is greatest positive integer n such that 2^n is a factor of 12^10?

a)10
b)12
c)16
d)20
e)60


Similar question to practice: what-is-the-largest-integer-n-such-that-2-n-is-a-factor-of-158297.html
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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
Nice One.
Here breaking down 12^10 => 2^20 *3^10
so 20 is our answer
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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
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Hi All,

This question comes down to exponent rules and how to 'rewrite' a number raised to a power.

12 = (2)(2)(3)

12^2 = (2^2)(2^2)(3^2) = (2^4)(3^2)
12^3 = (2^3)(2^3)(3^3) = (2^6)(3^3)

Seeing this pattern, you should be able to rewrite 12^10...

12^10 = (2^10)(2^10)(3^10) = (2^20)(3^10)

So the largest 'power of 2' that is a factor of 12^10 is 20.

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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
Expert Reply
Lets write \(12^{10} in the prime factors: (2 * 2 * 3)^{10}\)

=> \((2 ^2)^{10} * (3)^{10}\)

=> \((2)^{20} * (3)^{10}\)

The greatest possible value of n = 20

Answer D
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Re: What is greatest positive integer n such that 2^n is a factor of 12^10 [#permalink]
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