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a an integer

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a an integer

by jain2016 » Mon Mar 14, 2016 8:30 am
Is a an integer?

1) a^3 is an integer

2) The cube root of a is an integer

OAB

Hi Experts ,

Please explain.

Many thanks in advance.

SJ
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Source: — Data Sufficiency |

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by [email protected] » Mon Mar 14, 2016 9:53 am
Hi jain2016,

This DS question can be solved by TESTing VALUES or Number Properties.

We're asked if A is an integer. This is a YES/NO question.

1) A^3 is an integer.

IF...
A^3 = 1
A = 1
The answer to the question is YES.

IF...
A^3 = 2
A = (cube-root of 2)
The answer to the question is NO.
FACT 1 is INSUFFICIENT

2) The cube root of A is an integer

IF...
(cube-root of A) = 1
A = 1
The answer to the question is YES

IF...
(cube-root of A) = 2
A = 8
The answer to the question is YES

IF...
(cube-root of A) = -3
A = -27
The answer to the question is YES

IF...
(cube-root of A) = 0
A = 0
The answer to the question is YES
FACT 2 is SUFFICIENT

Final Answer: B

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