The four chests

The solution is 195 coins.

The first chest contains 15 gold coins.
The second chest contains $3\times 15=45$ coins.
The third chest contains a ninth of that, so $45/9=5$ coins.
The fourth chest contains $2\times(15+45+5)=130$ coins.

So the adventurers got $15+45+5+130=195$ coins.