Here is the best answer, in eleven manipulations:--

Treasure down.

Boy down--treasure up.

Youth down--boy up.

Treasure down.

Man down--youth and treasure up.

Treasure down.

Boy down--treasure up.

Treasure down.

Youth down--boy up.

Boy down--treasure up.

Treasure down.

Amusements in Mathematics · 第 908 / 970 题