Another beautiful puzzle from the same book as last time…”Mathematical Circle Diaries, Year 1″, by Anna Burago. This one is the last puzzle from Session 10.

Six stacks of coins are places on the table. The first has 1 coin, the second 2, and so on, until the last, which has 6 coins. You are allowed to select any two stacks and add one coin to each. Can you make all the stacks equal? You can repeat the operation as many times as you want to.

As always, please send your answers directly to me at alokgoyal_2001@yahoo.com. If you like the puzzle, please share it with others. If you have interesting puzzles to share, please send them to me at my e-mail given above.

Enjoy the increasing stacks of money!