Help 23 ​

Monthly interest rate  =  .035 / 12  = 7/2400

Five years

n  = 60

33000 (7/2400)   ( 1 + 7/2400)^ 60  /  [ ( 1 + 7/2400)^60 - 1 ]  ≈ $600.33 / mo

Six years

n = 72

33000 (7/2400)   ( 1 + 7/2400)^ 72  /  [ ( 1 + 7/2400)^72 - 1 ]  ≈ $508.81 / mo