How many factors of 42 are not factors of 56?
A. 1
B. 2
C. 3
D. 4
E. 5
The OA is D.
Experts, how can I solve this PS question? I don't have it clear. Thanks.
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How many factors of 42 are not factors of 56?
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Brent@GMATPrepNow
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The fastest approach is probably to just list the factors of 42 and 56swerve wrote:How many factors of 42 are not factors of 56?
A. 1
B. 2
C. 3
D. 4
E. 5
Factors of 56: {1, 2, 4, 7, 8, 14, 28, 56}
Factors of 42: {1, 2, 3, 6, 7, 14, 21, 42}
So, the factors of 42 that are NOT factors of 56 are: 3, 6, 21 and 42 (four numbers in total)
Answer: D
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Scott@TargetTestPrep
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42 = 2 x 3 x 7swerve wrote:How many factors of 42 are not factors of 56?
A. 1
B. 2
C. 3
D. 4
E. 5
The OA is D.
Experts, how can I solve this PS question? I don't have it clear. Thanks.
56 = 7 x 8 = 7 x 2^3
So, the factors of 42 that are not of 56 are 3, 3 x 2, 3 x 7, and 2 x 3 x 7.
Answer: D
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