Nine coins are placed in 8 rows of 3 coins each.

Move two coins and form 10 rows of 3 coins each.

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- July 23rd 2009, 09:28 PMSorobanCoin problem

Nine coins are placed in 8 rows of 3 coins each.

Move two coins and form 10 rows of 3 coins each.

- July 23rd 2009, 09:32 PMVonNemo19
Is that 8 supposed to be a three? I'm not very good at this stuff, could you explain how there can be nine coins in 8 rows of three.

- July 24th 2009, 01:02 AMOpalg
- July 24th 2009, 04:06 AMWilmer
How about 11 rows:

1 2 3

4 5 6

7 8 9

Put 4 and 6 on top of 5; then you have:

1 2 3

7 8 9

1 4 9

1 5 9

1 6 9

2 4 8

2 5 8

2 6 8

3 4 7

3 5 7

3 6 7

James F. Fixx: "everything that's not implicitly prohibited in a puzzle is allowed" - July 24th 2009, 04:21 AMOpalg
- July 24th 2009, 05:22 AMWilmer
- July 24th 2009, 06:55 AMSorobanThis is the standard solution:

__Spoiler__:

- July 24th 2009, 10:07 AMWilmer
Ok, Soroban.

But if 11 instead of 10, do you agree mine is "acceptable"?