Coin Stack Puzzle

[Gunjan Kumar]

Hi

Just one puzzle to puzzle you guys.

I have five stack of 100 coins each. each coin weighs 10 gm in 4 stack and in one stack of coin, each coin weight 9 gm.

I have one weighing SCALE. In how many minimum steps, will you be able find the 9 gm coins stack?
[ June 19, 2007: Message edited by: Gunjan Kumar ]

[Vikrant Pandit]

This is a really old puzzle ...

Take 1 coin from 1st stack , 2 from 2nd ....so on
Thus you will have 15 coins in total ..
Now weigh them ..

If 1st stack has 9 gms coins , the wieght will be 149 gms
If 2nd stack has 9 gms coins , weight will be 148 gms

and so on ..

[Gunjan Kumar]

Thanks Vivek