(12C) Mortgage Loan Interest Rate

[Albert Chan]

Timing suggested solving for i is using IRR routine.

Clear Reg
3600 CF0       ; PV
360 CHS CFj  ; PMT
36 Nj            ; N
IRR               ; 9.635443543 (17 sec)

9.23 [i] RCL [g] [R/S] ; guess = (-PMT/PV) - (-PV/PMT)/N^2 (10 sec)
       [i] RCL [g] [R/S] ; guess = true rate (4 sec)