The other fifty dollars represent the profit.

Now, aunt, I'll make you a regular business proposal.
If you'll lend me five hundred dollars, I'll give you my note for five hundred and fifty, bearing interest at six per cent., payable in six months, or, to make all sure, say in a year.

I place the ring in your hands, with leave to sell it at the end of that time if I fail to carry out my agreement.

But I sha'n't if I keep my health." The old lady was attracted by the idea of making a bonus of fifty dollars, but she was cautious, and averse to parting with her money.
"I don't know what to say, Ferdinand," she replied.

"Five hundred dollars is a good deal of money." "So it is, aunt.