Divisibility

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Divisibility

by relaxin99 » Wed Feb 04, 2009 8:16 pm
Is the interger K divisible by 4?

1) 8k is divisible by 16
2) 9k is divisible by 12

With the answer, can you all please explain how you came up with the answer thanks

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by DanaJ » Thu Feb 05, 2009 12:36 am
1. is insufficient, since if 8k is divisible by 16, this means that 8k = 16d (where d = quotient when you divide 8k by 16). This means that k = 2d, which means that k is even. However, we cannot tell if it is divisible by 4. If d is odd, then it sure isn't.

2. is sufficient, since if 9k is divisible by 12, this means that 9k = 12d (again, d = quotient). Since 9 is not divisible by 4 but it is divisible by 3, this means that k must be divisible by 12/3 = 4.
So k is divisible by 4.

Answer B.

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by relaxin99 » Fri Feb 06, 2009 4:46 pm
THank you very much Dana....wonderful explanation here

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by cramya » Sat Feb 07, 2009 1:18 am
Stmt I

k=2 NO
k=4 YES

insuff

Stmt II

9k/12 = a (where a is some integer)

3k/4 = a

3 is not divisible by 4 so k must be divisible by 4 for 3k/4 to be an INTEGER

SUFF

Choose A

Regards,
CR