The man who came to the shop was polite and unhurried, and his offer was simple. He would lend Zarina the money for the new freezer, and she would pay him back over a year, at interest of only three percent a month.
Three a month, she thought. Twelve months. That is thirty-six percent a year. High, but she knew what the freezer would earn her, and thirty-six she could carry.
Her daughter, who was home from university, asked to see the paper before her mother signed it. Then she asked one question: in the second month, is the three percent taken from what I borrowed, or from what I still owe?
From what she still owed. Which meant the second month's three percent was larger than the first month's, and the third larger again.
The daughter worked it through on the back of a receipt. Over twelve months the debt did not grow by thirty-six percent. It grew by just under forty-three. On a large enough loan, that gap was most of a month's profit from the freezer.
Zarina did take the loan, in the end, from a bank, at a rate she could compare properly. What her daughter had given her was not an answer about freezers. It was the habit of asking what a percentage is taken from, before agreeing to it.