Saturday, April 17, 2010

What is the number?

If you divide the number by 2 there will remainder of 1.
If you divide the number by 3 there will remainder of 1.
If you divide the number by 4 there will remainder of 1.
If you divide the number by 5 there will remainder of 1.
If you divide the number by 6 there will remainder of 1.
If you divide the number by 7 there will remainder of 1.
If you divide the number by 8 there will remainder of 1.
If you divide the number by 9 there will remainder of 1.
If you divide the number by 10 there will remainder of 1.
If you divide the Number by 11 there will remainder of 0.

15 Comments:

Blogger James said...

This post has been removed by the author.

April 17, 2010 11:25 PM  
Blogger James said...

is it 34560?

April 17, 2010 11:27 PM  
Blogger Ragknot said...

James,

No, it is not 34560

34560 / 2 has a remainder of zero.
The correct number would have a remainder of 1.

April 18, 2010 12:11 AM  
Blogger Wizard of Oz said...

10! (= 3,628,800) is divisible by all numbers 2 to 10.
So 10! + 1 (= 3,628,801) gives a remainder of 1 in each case.
It also happens to be divisible by 11.
There may be smaller numbers which also fit the requirements but I haven't checked.

April 18, 2010 1:15 AM  
Blogger Chris said...

Tle lowest common multiple of 2,3,...,10 is 2520. So 2520 has
remainder 0 after dividing by 2,3,...,10. So 2520x+1 has remainder
1 after dividing by 2,3,...,10. But 2520 mod 11 = 1.
We want n = 2520x + 1 = 0 (mod 11) => n = x + 1 = 0 (mod 11)
=> x = 10 and n = 25201.

April 18, 2010 7:06 AM  
Blogger Ragknot said...

I saw 36 numbers less than one million that works to fit this.

April 18, 2010 7:37 AM  
Blogger Ragknot said...

Chris found the first of the 36!!

April 18, 2010 7:38 AM  
Blogger Ragknot said...

Wiz found the 131st number that fits.

April 18, 2010 7:57 AM  
Blogger Chris said...

In my previous (which was for the smallest positive integer that does
the job), you can add multiples of 11 to x =>
2520(10+11y)+1 = 25201 + 27720y for y = 0,1,2... all do the job.

April 18, 2010 7:59 AM  
Blogger Ragknot said...

This post has been removed by the author.

April 18, 2010 8:05 AM  
Blogger Karl Sharman said...

Yup, 25,201.

April 18, 2010 8:20 AM  
Blogger Ragknot said...

This post has been removed by the author.

April 18, 2010 10:29 AM  
Blogger Ragknot said...

Sub test2()
While i < 200
n = n + 11
For m = 2 To 11
____j = n Mod m
____If m = 11 And j = 0 Then
________i = i + 1: Debug.Print i, n
____Else
________If j <> 1 Then Exit For
____End If
Next m
Wend
End Sub

April 18, 2010 12:02 PM  
Blogger Avi said...

is it?
3628801?
10!+1=3628801

April 25, 2010 8:34 PM  

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