Forensic Financial Tests

These are the tests which can give you quite a good profile and accuracy rating for your financial calculator. Any more contributions and confirmation are very much appreciated and I will update the swissmicros page (though I may need to move it off there at some point).

| #  | Ref        | N            | I%YR      | PV       | PMT          | FV        | P/YR | Mode  |
|----|------------|--------------|-----------|----------|--------------|-----------|------|-------|
| 1  | DM         | 38 x 12      | 5.25%     | 270'000  | ?            | 0         | 12   | end   |
| 1b | DM         | 38 x 12      | ?         | 270'000  | -14'584/12   | 0         | 12   | end   |
| 2  | SlideRule  | 360          | 15% → 12% | 100'000  | ?-?          | 0         | 12   | end   |
| 3  | Kahan 1983 | 60x60x24x365 | 10%       | 0        | -0.01        | ?         | =N   | end   |
| 4  | DM         | 480          | 0 → ?     | 100'000  | ?→ PMT       | 0         | 12   | end   |
| 5  | Dieter     | 10           | ?         | 50       | -30          | 400       | 1    | end   |
| 6  | Dieter     | 10           | ?         | 50       | -30          | 80        | 1    | end   |
| 7  | A Chan     | 10           | ?         | -100     | 10           | 1e-10     | 12   | end   |
| 8  | Miguel     | 32           | ?         | -999'999 | 0            | 1e6       | 1    | end   |
| 9  | DM         | ?            | 25        | 100000   | -2083.333334 | 0         | 12   | end   |
| 10 | DM         | ?            | 25        | 100000   | -2040.816327 | 0         | 12   | begin |
| 11 | robve      | 60x24x365    | 1/6% → ?  | 0        | -0.01        | ?→ FV     | =N   | end   |
| 12 | robve      | 40           | ? → I%YR  | 900      | -400         | -1000 → ? | 1    | begin |

2: https://www.hpmuseum.org/forum/thread-20707.html
3: https://www.hpmuseum.org/forum/thread-1012.html
5, 6: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv021.cgi?read=234439
7: https://www.hpmuseum.org/forum/thread-18359-post-161549.html#pid161549
8: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.cgi?read=120592
11, 12: https://www.hpmuseum.org/forum/thread-16565-page-2.html

Puzzle 2 is from here, and needs you to calculate PMT given n = 360, I%YR = 15%, PV = 100'000, FV = 0, then calculate PMT, but with I%YR = 12%. Subtract the two results, and put that back into PMT, then change n = 36 and I%YR = 15% again, and calculate PV.

Puzzle 3: you may need to divide I%PY by N depending on how your calculator handles i vs I%YR and what the limit is on P/YR.

Puzzle 4 needs you to calculate PMT first given I%YR = 0, then re-input this back into PMT and calculate I%YR. On the HP-12c this is best done by pressing x<>y twice before putting back into PMT.

Puzzle 11: calculate for FV first, re-input back to FV and compute I%YR.

Puzzle 12: calculate for i first, re-input back into i and compute FV.

The other puzzles are just a solve for '?'.

They can be a bit confusing, so I also did a couple of videos here and here solving them on a DM-42 and HP-12c.