GMAT Focus Question

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GMAT Focus Question

by Abdulla » Fri Dec 19, 2008 6:02 pm
If n and k are positive integers, what is the remainder when 3^(4n+2) +k is divided by 10 ?

(1) k=1
(2) n=5
Abdulla
Source: — Data Sufficiency |

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Re: GMAT Focus Question

by logitech » Fri Dec 19, 2008 6:28 pm
Abdulla wrote:If n and k are positive integers, what is the remainder when 3^(4n+2) +k is divided by 10 ?

(1) k=1
(2) n=5
3^(4n+2) +k = 9^(2n+1) + k

2n+1 is an odd number and for odd numbers, 9^(2n+1) has 9 in its unit digit. 9, 729, ..etc

st1) k =1 than the 9^(2n+1) + k will end with 0 and the remainder will be 0 when divided by 10 - SUF

st2) no info for K - INSUF

choose A
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by Abdulla » Fri Dec 19, 2008 6:50 pm
This is the right answer and nice approach..
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Re: GMAT Focus Question

by vilavb » Fri Dec 19, 2008 7:29 pm
logitech wrote:
Abdulla wrote:If n and k are positive integers, what is the remainder when 3^(4n+2) +k is divided by 10 ?

(1) k=1
(2) n=5
3^(4n+2) +k = 9^(2n+1) + k

2n+1 is an odd number and for odd numbers, 9^(2n+1) has 9 in its unit digit. 9, 729, ..etc

st1) k =1 than the 9^(2n+1) + k will end with 0 and the remainder will be 0 when divided by 10 - SUF

st2) no info for K - INSUF

choose A
iN THE ABOVE QUESTION WHAT DOES THIS SIGN "^" DENOTE???

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by cramya » Fri Dec 19, 2008 7:34 pm
iN THE ABOVE QUESTION WHAT DOES SIGN "^" DENOTE???
Exponentiation or power something is raised to

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by logitech » Fri Dec 19, 2008 8:05 pm
cramya wrote:
iN THE ABOVE QUESTION WHAT DOES SIGN "^" DENOTE???
Exponentiation or power something is raised to
2x2x2x2 = 2 ^FOUR
( four )
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