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If a positive integer n is divisible by both 7 and 9, then n must be d
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04 Jul 2023, 04:28
04 Jul 2023, 04:28
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Question Stats:
54% (00:54) correct
45% (01:10) wrong based on 11 sessions
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If a positive integer n is divisible by both 7 and 9, then n must be divisible by which of the following?
A. –9
B. –3
C. 3
D. 21
E. 63
Post A Detailed Correct Solution For The Above Questions And Get Kudos.
Question From Our Project: Free GRE Prep Club Tests in Exchange for 20 Kudos
\(\Longrightarrow\) GRE - Quant Daily Topic-wise Challenge
\(\Longrightarrow\) GRE NUMBER PROPERTIES
A. –9
B. –3
C. 3
D. 21
E. 63
Post A Detailed Correct Solution For The Above Questions And Get Kudos.
Question From Our Project: Free GRE Prep Club Tests in Exchange for 20 Kudos
\(\Longrightarrow\) GRE - Quant Daily Topic-wise Challenge
\(\Longrightarrow\) GRE NUMBER PROPERTIES
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Official Answer
A,B,C,D,E
Re: If a positive integer n is divisible by both 7 and 9, then n must be d
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07 Aug 2023, 09:19
07 Aug 2023, 09:19
Expert Reply
OE
Using the concept that if a number is divisible by 𝑥 and by 𝑦, it must be divisible by LCM of 𝑥and 𝑦.
Since, 𝑛 is divisible by both 7 and 9, thus it must definitely be divisible by LCM (7, 9) = 63
Now, as 𝑛 is divisible by 63, it will definitely be divisible by all the factors of 63 which can divide 63 completely.
Thus, 𝑛 must be divisible by −9, −3, 3, 21, 63
Ans. (A, B, C, D, E)
Using the concept that if a number is divisible by 𝑥 and by 𝑦, it must be divisible by LCM of 𝑥and 𝑦.
Since, 𝑛 is divisible by both 7 and 9, thus it must definitely be divisible by LCM (7, 9) = 63
Now, as 𝑛 is divisible by 63, it will definitely be divisible by all the factors of 63 which can divide 63 completely.
Thus, 𝑛 must be divisible by −9, −3, 3, 21, 63
Ans. (A, B, C, D, E)
gmatclubot
Re: If a positive integer n is divisible by both 7 and 9, then n must be d [#permalink]
07 Aug 2023, 09:19
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