HP 10bii+ Margin/Markup bug

[Rick314]

I have a 17BII too, and found other issues with how these subjects are implemented on various HP calculators. For example:

Code:

HP 17BII           HP 200LX, HP CALC, Bus%   HP 10BII+
=================  =======================   ==============
OLD NEW %CH        OLD NEW %CHG              MU CST PRC MAR
TOTAL PART %T      TOTAL PART %TOTAL
COST PRICE M%C     
COST PRICE M%P     More (separate screen)
                   =======================  
                   COST PRICE MARKUP MARGIN

Solver no L(),G()  Solver has L(),G()

None of the above will solve for Margin given Markup or vice versa.

The 17BII "OLD NEW %CH" and "COST PRICE M%C" are the same math with different variable names.

The 200LX "OLD NEW %CHG" and "COST PRICE MARKUP" are the same math with different variable names.

The 200LX Solver has function L() (Let variable equal expression, needed for my Solver function earlier in this thread) but the 17bII is missing it.

The 17BII "M%C" ("MARKUP%C" when solved) and "M%P" ("MARKUP%P" when solved) should be PROFIT (price - cost) as a percentage of Cost or Price, not MARKUP as a percentage of Cost or Price. The wrong word is used.

The 10bII+ MAR key can mean either MARkup or MARgin, a confusing choice of a key legend.

The 200LX variable order (COST PRICE MARKUP MARGIN) seems more logical than the 10bII+ (MarkUp CoST PRiCe MARgin).

3/31/21 Edit: REVENUE changed to PROFIT (error correction).

[Gamo]

Was looking in the HP-18C Business Consultant Owner's Manual

On page 53 about Sharing Variables Between Menus

If you compare the MU%C menu and the MU%P menu, you'll see that they
have two menu lables in common are [COST] and [PRICE]:

The HP-18C keeps track of the values you key in according to those labels.

Example: Using shared variables.

Part 1. Cost = 9.60 Markup = 15% What is the Price?
Part 2. What is the markup on price (Margin)?

[BUS] [MU%C] // Display the MU%C menu.

9.60 [COST] // Store 9.60 in COST.
15 [M%C] // Store 15% in M%C (Markup)

[PRICE] 11.04 // Calculate the PRICE

Part 2.
[EXIT]

[MU%P] // Exit the MU%C menu and enter the MU%P menu

[M%P] 13.04 // Calculate the markup as a percent of price (Margin)

--------------------------------------------------------------------
I don't have the HP-18C so I'm not sure if start to store [PRICE] [M%P]
can it be solve for [COST] and [M%C]

Gamo

[Rick314]

(04-01-2021 12:55 PM)Gamo Wrote:  ... HP-18C Business Consultant ...
Example: Using shared variables
Part 1. Cost = 9.60 Markup = 15% What is the Price?
Part 2. What is the markup on price (Margin)?

Thank you Gamo, but this is the same as the 17BII and demonstrates the same problem that started this thread. It can't solve all 12 mathematically possible input-output scenarios without doing a required entry-solve sequence ("Part 1", "Part 2") and finding intermediate values that are sometimes unnecessary. The HP 200LX HP CALC Solver solution given 3/27/21 converts from 15% Markup to 13.04% Margin directly (no need for Cost or Price at all), or any other mathematically possible from-to situation: Enter Markup and Cost, Solve for Price (and you get Margin too); Enter Markup and Cost, Solve for Margin (and you get Price too); ... 12 scenarios total. All HP calculators could have done this, but none do so.

[Gamo]

The HP-37E Financial Calculator I believe that this is the only HP calculator that

can calculate between Mark Up and Margin by the use of the [PRICE] function.

If you have the 37E User's Handbook this [PRICE] feature on page 10

This user manual never memtion the term call " Margin " instead it called

Markup based on selling price.

---------------------------------------------------

Example from manual:

Harry's Bait and Tackle Shop can purchase crab pots for $5.60. If Harry desires to maintain
a markup of 60% based on the selling price, how much is the selling price?

60 [ENTER] display 60.00 // Enter markup then cost.
5.6 [f] [PRICE display 14.00 // Selling price.

So the 60% is the "Margin" and 5.6 is the "Cost"

The formula for PRICE is X ÷ [1 - (Y ÷ 100) ] where x is the purchase cost and
y is markup based on selling price.
--------------------------------------------------
On page 11 shown how to convert beween Mark Up and Margin

As state in the manual:

You many want to convert the percent of markup from a selling cost base to a purchase cost
base or vice versa. You can do this with the [PRICE] key.
Let's look at two examples.

1. If an item is sold at a 30% markup based on selling price, what is the equivalent markup based on cost?

30 [ENTER] display 30.00 // % markup based on selling price.
[f][PRICE] display 42.36 // % markup based on purchase cost.

2. If an item is sold at a 70% markup based on the purchase cost, what is the equivalent markup based on sellin price?

70 [CHS] [ENTER] display -70.00 // Change sign of markup based on cost and [ENTER]
[CHS] dispaly 70.00 // Now the Y- and X-registers have the correct values for the calculation
[f] [PRICE] display 41.18 // % markup based of selling price.

Remark:
Example #2 basically is to convert Markup to Margin so in order to use Markup the value
must enter as negative by [CHS] key.
---------------------------------------------------

Gamo

[Rick314]

Thank you for the interesting HP-37E information Gamo. It shows another way HP handled the Price, Cost, Markup, Margin problem, but still not covering all possible input-solve combinations. The HP 200LX HP CALC solution given in this thread 3/27/21 handles all 12 possible cases:

Code:

Inputs          Solve For
=============   ===========
 4 CST  5 PRC   MU  (& MAR)
 4 CST  5 PRC   MAR (& MU)
 4 CST 25 MU    PRC (& MAR)
 4 CST 25 MU    MAR (& PRC)
 4 CST 20 MAR   PRC (& MU)
 4 CST 20 MAR   MU  (& PRC)
 5 PRC 25 MU    CST (& MAR)
 5 PRC 25 MU    MAR (& CST)
 5 PRC 20 MAR   CST (& MU)
 5 PRC 20 MAR   MU  (& CST)
25 MU           MAR
20 MAR          MU

As an example, I attached an image of what the 200LX display looks like after Clear Data, 4, CST, 25, MU, MAR. HP could have handled all 12 cases like this in their Cost-Price-Markup-Margin calculators but didn't.

[Gamo]

Sorry for this one cause is not HP related.

I program this Pricing Calculations using the Python code.

This code can be run and view the code on the web.

So that one who really interest can see the algorithm I used
for this program.

Link: https://trinket.io/python/656c020f51?runOption=run

For choice Program #1

Enter the two unknown with 0
If enter 0 on both Cost and Price one of the Markup and Margin must
Have a value so this can be converted between MU and MAR

Gamo

[Gamo]

Here is the manual ways of doing the Pricing Calculations

https://youtu.be/EErZmyovaC8

gamo