Question 401260
Principal(P)= $15,000
Period of payment(n)= 36mths
Installments(X) = $500
monthly interest rate(r)= ?

20% down payment so the principal or balance of the loan will 15,000-(20%*15000) which is $12,000.
Hence the equation is Present value because you borrow the amount today.
so {{{PV= X * ((1-(1+r)^(-n))/r)}}}
where Pv is the principal. Therefore solving for the monthly rate will be;
{{{12000= 500 * ((1-(1+r)^(-36))/r)}}}