I tried a lot but got wrong answer everytime

Erin purchased a Ford Bronco valued at $26,000. As a down payment, she paid 15% of the cost, and agreed to make equal payments at the end of each month for five years. Interest is 8% compounded monthly. Round your final answers to the nearest cent. (a) The size of the monthly payment is $ (b) The outstanding principal balance after 24 payments is $