BdMO National Primary 2011/8

Discussion on Bangladesh Mathematical Olympiad (BdMO) National
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Moon
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BdMO National Primary 2011/8

Unread post by Moon » Fri Feb 11, 2011 12:25 pm

Problem 8:
If $3$ and $4$ individually divides a number, then also divides that number. For example, all of $3, 4$ and $12$ divide $48$. But if a number is divisible by $3$ and $6$ individually it may or may not be divisible by $3 \times 6=18$ . For example, both of $54$ and $60$ are divisible by $3$ and $6$ individually, though only $54$ is divisible by $18$. Can you explain why this happens?
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samiul_samin
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Re: BdMO National Primary 2011/8

Unread post by samiul_samin » Fri Feb 22, 2019 7:43 am

Because the mentioned rule is applicable only for co-prime numbers.
And prime power factorization is the main reason of any number divisibility by other numbers.

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