Starting piont

We put ourself in the poor situation, we need money, lets say about 100 000 Euro, and we haven't any other opportunity, except borrowing it. In the real world there are many different types of loans. Before putting the signature on the right place of the contract, we have to choose one credit. Which one will fit perfectly? It's obvious, everybody tries to get the best credit! Such a scenario allows many mathematical questions on different intellectual levels, from school to research. Again, the article's focus is on secondary education. We deduce the problem: "Which credit is the best?"