Joshua borrows $94500 to purchase his house. The loan is over 25 years at 10% p.a interest compounded on the balance owing after each monthly repayment

i) Calculate the value of his monthly repayments.

I got $856 but that is not the answer >< using the principal that:

94500 x (1.0083^300-1) = a(1.0083^300 -1)/(1.0083-1)

Thank you for help given.