Since we are trying to figure out what your monthly payment should be, let's
use the variable p to stand for it for the time being. At the end of each
month you must pay 7/12% of the current loan balance in interest. Clearly,
you and the bank want your monthly payment to be sufficient to at least cover
the interest each month. Can you calculate a lower bound on the monthly
payment?

Click here for the answer

The first month the loan balance will be $100,000, so we must pay 7/12% of
this, or $583.33, in interest. If this were our entire monthly payment, we
would never make any progress at paying off the loan. Our monthly payment,
then, must be larger than this.