A $150 bicycle was purchased on Dec 1 with a $15 downpayment. The balance is to be paid at the rate of $10 at end of each month, with the first payment due on Dec 31. The last payment may be some amount less than $10. If interest on the unpaid balance is computed to be 1.5% per month, how many payments will there be, and what is the amount of the final payment?