The slope is -2. In context to this problem, the candle will burn away 2cm of its length every hour.
The first misconception is that the balance shouldn't be paid off in full in order to boost the credit score. This is simply not true. You can pay off all of the balance and it will actually improve the score. The score reflects the ability to pay borrowed money back. A credit card is basically a micro-loan of sorts. So if George pays off the balance, he's paying back the credit card company and that tells the company (and others) that his ability to pay is good. Plus it tells about his priorities which is what the credit score indirectly indicates. Other companies will see that George can pay the money back, so they'll be more eager to lend to him.
The other misconception is that being late is fine and improving the payment habits is what brings up the score. This is murky gray area and somewhat true but also somewhat false. What happens is that if you are late then your score goes down by some amount. When you improve the payment habits, the score goes back up. Whether it goes back to the original value or larger depends on the situation. So the second claim George makes is technically true, but there's broader context to consider. It's similar to how if you shoot yourself in the foot in some videogame, and then let your foot heal up, then you're increasing health points. The first act shouldn't have needed to happen and it reflects a weird backwards thinking. If anything, it wastes time where George could have simply been improving the score (rather than decrease it only to increase it back).
The reality is that keeping up with the payments in a timely fashion is what keeps the credit score healthy. Once again, the score reflects someone's ability to pay back borrowed money. It applies to any kind of loan, which a credit card is a part of.
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In short, George is mistaken by two claims he makes
- Not paying off the balance in full improves the credit score
- Being late on payments, and then improving payment habits, will increase the credit score
When in reality keeping up with payments and paying off the balance will improve the credit score. There's no need to hinder oneself on purpose in the goal of improving from that contrived setback.
Side note: the credit card company wants you to carry a balance so they can charge interest on said balance. That's how they make most of their money. However, even if you go against the wishes of the credit card company, they won't ding you credit score points for paying off the balance in full.
