Tommy never pays his credit card in full so he always pays a finance charge. This month, he starts with a daily balance of $$900.$ He wants to pay his insurance payment of $$1500$ with his credit card this month. If he pays his insurance on the first day of the month and doesn't buy anything else for the rest of the $30-$day cycle, what is his average daily balance $?$

If Tommy's interest rate is $22\mathrm{.}9\%,$ what is his finance charge for the month?

If Tommy decided to pay his insurance on the last day of the $30$ day cycle instead of the first day, what would his average daily balance be$?$

If Tommy decided to pay his insurance on the last day of the $30-$day cycle instead of the first day, what would his finance charge be$?$

How much money would Tommy save by paying his insurance at the end of the month rather than the beginning?