A is in decimal representation : http://www.mathramz.com/xyz/latexren...d6b4f14a65.png

Find all naturAls numbers. X , Y.. so that A divide by 25 .(Rofl)

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- Aug 4th 2009, 08:32 AMdhiabFind all naturAls numbers. X , Y..
**A is in decimal representation : http://www.mathramz.com/xyz/latexren...d6b4f14a65.png**

**Find all naturAls numbers. X , Y.. so that A divide by 25 .(Rofl)** - Aug 4th 2009, 08:45 AMGamma
Maybe I am misunderstanding something, I don't know.

so your number can be written:

$\displaystyle A=100\cdot xyxyxyxyx + y5$

where these are the decimal representation.

$\displaystyle 25|100$, so you need only worry about when $\displaystyle 25|y5$ which is clearly only 25 or 75.

so $\displaystyle y=\{2,7\}$

$\displaystyle x=\{0,1,2,3,4,5,6,7,8,9\}$ - Aug 4th 2009, 08:49 AMGammafurther reflection
unless x and y can represent multiple digit numbers?

Then $\displaystyle y=\{n\in \mathbb{N}|n$ ends in a 2 or a 7}

$\displaystyle x=\mathbb{N}$