Question 1132676
The monthly payment can be found by using the following formula:
{{{M = (P(1+r)^n*r)/((1+r)^n-1)}}}
where
  P  = Present Value (beginning value or amount of loan)
  r   = Periodic Interest Rate = APR/ # of interest periods per year
  M   = Monthly Payment
  n   = # of interest periods for overall time period (i.e., interest
        periods per year * number of years)


Plugging in your values, you would get.
{{{r = 0.045/12}}}
{{{r = 0.00375}}}

PLuging in "r"
{{{M = (P(1+r)^n*r)/((1+r)^n-1)}}}
{{{M = (40000(1+0.00375)^84*(0.00375))/((1+0.00375)^84-1)}}}
{{{M = (205.4178)/((1+0.00375)^84-1)}}}
{{{M = (205.4178)/(.3695)}}}
{{{M = 556.009}}}

In Money:
$556.01 per month for 84 months. You end up paying a total of $46,704.54 and pay $6,704.54 in interest.