Chloe Colburn purchased home appliances for her new apartment. Store allowed her to defer payments (interest is still being charged even though payments are deferred) for six months and to make 36 equal end-of-month payments thereafter. The original note was for $15,000, with interest at 9% per annum compounded monthly. After 26 monthly payments, Chloe considers getting a loan from the bank to pay her debts in one lump sum. She would pay the bank $186 per month for the next 30 months.

1. a) Find the original monthly payment made to the store.
2. b) Find the lump-sum payoff amount she needs to take loan from the bank.
3. c) What monthly rate of interest is the bank charging on this loan?