This particular problem is deceptive (and intentionally so) because it gives you a logic that has an inconsistent frame of reference.
So let us examine the facts, then process into the account, shall we?
To simplify things, the three men will be considered a single party, as there really isn't anything distinguishing one from the other.
1) The Men pay the Manager $30.
2) The Manager hands the Bellhop $5.
3) The Bellhop hands the Men $3.
Three transactions, now let us track where the $30 is
Before step one, the Men have $30, and the Manager and Bellhop have $0 each.
After payment, the Manager has $30, and the Bellhop and Men $0.
After the Manager tasks the Bellhop, the Manager has $25 (NOT $27), the Bellhop $5, and the Men $0.
After the Bellhop performs the incomplete refund, the Manager still has $25, the Bellhop $2, and the Men $3. Sum total is $30.
So as the second poster has pointed out, the $27 paid includes both the Manager's revenue and the Bellhop's "fee", and the remaining $3 is back with the men.