Finance problems (TVM) on hp 49G+ hp 50G Periods and compounds per year are different

[Werner]

in case C/YR divides P/YR (which is the case here):
60 [N] 3e4 [PV] -565.7117265 [PMT] 0 [FV] [END] [i] -> 0.414087533
-3 * [PMT] 0 [PV] 4 [N] [FV] -> 5.000
( [RCL] [i] CYR [CHS] [*] [PMT] 0 [PV] PYR [ENTER] CYR [/] [N] [FV] -> I%YR )

Cheers, Werner

explanation: (corrected.. thanks, Albert!)

             I%YR/CYR  CYR/PYR
i% = [ ( 1 + -------- )       - 1 ]*100
               100


now we must find I%YR !

               i%  PYR/CYR
I%YR = [ ( 1 + --- )        - 1 ]*CYR*100
               100
                           (1 + i%/100)^N - 1
now, remember USFV(i%,N) = -----------------
                                i%/100

and PV*(1+i%/100)^N + PMT*USFV(i%,N) + FV = 0

so if we take N=PYR/CYR, PV=0 and PMT = -i%*CYR, FV will give us I%YR