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 Inverting Triangles (Posted on 2005-08-15)
A piece of paper had the following diagram:
```               o              o o o o
From:   o o         To:  o o o
o o o              o o
o o o o              o
```
Below it, it read "Given the initial formation of ten coins, move exactly # coins to produce the end formation." It was pretty obvious that # stood for a digit, but it was smudged and couldn't be read. What possible numbers could it have been so the problem was solvable?

To allow explaining the solution, number the coins like this:

```           0
1 2
3 4 5
6 7 8 9
```
Note: This problem was inspired by a forum question by Nicole.

 No Solution Yet Submitted by Erik O. Rating: 2.1667 (6 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
 re(2): 7 ways | Comment 10 of 14 |
(In reply to re: 7 ways by Nosher)

Good point, but interesting to explore.
 Posted by brianjn on 2005-08-16 02:53:44

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