First, we need to determine how much she pays in 4 years
P = r( PV)
-----------
1 - ( 1+r) ^-n
where P = payment
PV = present value
r = rate per period
n = number of periods
PV = 10000
r = .0825/ 12 =.006875
n = 4 years = 48 months
P = .006875(10000)
----------------------
1-(1+.006875)^-48
The monthly payment is 245.30
Times 48 months = 11774.40
Changing to 3 years = 36 months
P = .006875(10000)
----------------------
1-(1+.006875)^-36
P = 314.52
Times 36 months =11322.72
Taking the difference
11774.40-11322.72=451.68
She will save 451.68