## Search found 23 matches

- Tue Jan 13, 2015 10:50 pm
- Forum: Combinatorics
- Topic: n+1 rows and columns
- Replies:
**10** - Views:
**3237**

### Re: n+1 rows and columns

Actually I wanted to count the number of black cells we need "at least" & present them as the intersections so that i can prove there "always" exists $i$ rows & $j$ columns with given condition.

- Sun Jan 11, 2015 11:08 pm
- Forum: Combinatorics
- Topic: n+1 rows and columns
- Replies:
**10** - Views:
**3237**

### Re: n+1 rows and columns

We want to colour the least possible cells in black so that all the $n!$ sets may have at least one black cell. And this is possible by colouring all the cells of a row/column black. Now each cell can be described as the intersection of a row and a column. In the above case where we wanted to colour...

- Fri Jan 09, 2015 8:41 pm
- Forum: Junior Level
- Topic: Birthday Cake
- Replies:
**3** - Views:
**2956**

### Re: Birthday Cake

Well, not giving the answer directly.

You know, one can eat more than one piece but not a fractional portion of a piece.

You know, one can eat more than one piece but not a fractional portion of a piece.

- Tue Oct 14, 2014 11:38 pm
- Forum: Number Theory
- Topic: Arithmetic series in Fibonacci
- Replies:
**5** - Views:
**2264**

### Re: Arithmetic series in Fibonacci

But subsequence does not necessarily need to be of consecutive terms of the original sequence, does it?

- Wed Oct 01, 2014 11:24 pm
- Forum: Number Theory
- Topic: Dat cool problem
- Replies:
**3** - Views:
**1442**

### Re: Dat cool problem

I think the term was $\frac{{a_{i-1}}^2+{a_i}^2}{2}$ in our exam!

- Fri Sep 19, 2014 12:06 pm
- Forum: Number Theory
- Topic: Magic-Square preserving functional equation(Self-made)
- Replies:
**4** - Views:
**1569**

### Re: Magic-Square preserving functional equation(Self-made)

Anyway, you can only divide by r, if this is a common factor of all the entries!

- Fri Sep 19, 2014 11:12 am
- Forum: Number Theory
- Topic: Magic-Square preserving functional equation(Self-made)
- Replies:
**4** - Views:
**1569**

### Re: Magic-Square preserving functional equation(Self-made)

If we have a $n*n$ magic square with entries $(a_1, a_2,..., a_{n^2})$ , we can simply make another magic square with entries $(a_1\pm r, a_2\pm r,..., a_{n^2}\pm r)$ , where $r$ is a positive integer. because then the sum of each row or column will be increased or decreased by $nr$ . And the same g...

- Tue Sep 03, 2013 7:30 pm
- Forum: News / Announcements
- Topic: Online Geometry Camp 2014 Phase 1
- Replies:
**19** - Views:
**7737**

### Re: Online Geometry Camp 2014 Phase 1

@নায়েল ভাইয়া,

আমাদের যে দুই টা পরীক্ষা হল, এগুলোর ফলাফল কি জানানো হবে? হলে কবে?

আমাদের যে দুই টা পরীক্ষা হল, এগুলোর ফলাফল কি জানানো হবে? হলে কবে?

- Sat Aug 31, 2013 8:32 pm
- Forum: National Math Camp
- Topic: [OGC1] Online Geometry Camp: Day 5 (EXAM!)
- Replies:
**29** - Views:
**11697**

### Re: [OGC1] Online Geometry Camp: Day 5 (EXAM!)

nayel wrote:Ira, did you email or pm me your solutions? I've checked both but can't seem to find them.

Nayel vaia, I have sent you email. it is still in my sent item.

As you didn't find it. I am resending.

- Sat Aug 31, 2013 6:32 pm
- Forum: National Math Camp
- Topic: [OGC1] Online Geometry Camp: Day 5 (EXAM!)
- Replies:
**29** - Views:
**11697**

### Re: [OGC1] Online Geometry Camp: Day 5 (EXAM!)

vaia, I have received a reply for Exam 02. but didn't get for Exam 01. Did you get my solutions of Exam 01?nayel wrote:I've replied to everyone who has sent me solutions. If you didn't get a reply, let me know asap.