## Rangpur Secondary 2011/6

Problem for Secondary Group from Divisional Mathematical Olympiad will be solved here.
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Please don't post problems (by starting a topic) in the "Secondary: Solved" forum. This forum is only for showcasing the problems for the convenience of the users. You can post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.
Moon
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### Rangpur Secondary 2011/6

Problem 6:
When \$N\$ is divided by \$7\$, the quotient is twice the remainder. What is the number greater than \$7\$ that must divide \$N\$?
"Inspiration is needed in geometry, just as much as in poetry." -- Aleksandr Pushkin

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Tahmid Hasan
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### Re: Rangpur Secondary 2011/6

is the wanted number a prime?
if it isn't there is no soln.
let's express \$N=7.2a+a\$
let's input the possible values of \$a=1,2,3,4,5,6\$
then the numbers are not divisible by any prime greater than 7
বড় ভালবাসি তোমায়,মা

Mehfuj Zahir
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### Re: Rangpur Secondary 2011/6

N=15a then must be divided by 15

leonardo shawon
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### Re: Rangpur Secondary 2011/6

no..actually it is if \$N=15x\$ [\$x=1,2] and divisible by 7 then quotient is twice the remainder.
Ibtehaz Shawon
BRAC University.

long way to go .....

Mehfuj Zahir
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### Re: Rangpur Secondary 2011/6

For any natural number it is true.U should read the question carefully.

leonardo shawon
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### Re: Rangpur Secondary 2011/6

sorry. Mistake
Ibtehaz Shawon
BRAC University.

long way to go .....

Moon
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### Re: Rangpur Secondary 2011/6

No problem. We are here so that we may discuss and learn from our mistakes.
"Inspiration is needed in geometry, just as much as in poetry." -- Aleksandr Pushkin

learn how to write equations, and don't forget to read Forum Guide and Rules.

*Mahi*
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### Re: Rangpur Secondary 2011/6

Here,\$N\$ must be equal to \$15x\$ where \$x\neq7y\$.Then \$15\$ is the answer.