---

@Rose101 wrote:

it does not specify the interest rate. Is that rate known or predictable

For the penalty on the unpaid balance, it says you will be charged 1/2 of 1% for each month 

  What do they mean by the maximum penalty is 25%?

---

Interest rate is announced and can change every quarter (see link).

At 1/2% per month, after 50 months of non-payment it will have hit the maximum 25% penalty.  In your example, $25.