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#1 Re: Help Me ! » bank interests » 2019-09-23 12:47:14

Hi Bob and Hannibal;

bob bundy wrote:

I used Microsoft Excel to do a few years' calculations.

That would be "a few months' calculations", Bob.

bob bundy wrote:

You should be able to see that the 'Principle' is gradually going down but not as fast as you thought.

I try not to drop my principles, but this $10,000 principal fairly plummeted! Test spotted, Bob! smile

Hannibal lecter (post #8) wrote:

balance = 10,000 + 0.5% = 10050
now 10050 - $500 = 9950
now add 9950 + 0.5% = 9597.75
after that again sub 9597.75 - $500

The algorithm is right, but there are two errors in the figures. They should read:

balance = $10,000 + 0.5% = $10050
now $10050 - $500 = $9550
now add $9550 + 0.5% = $9597.75
after that again sub $9597.75 - $500

Hannibal lecter (post #2) wrote:

Every month, $500 is withdrawn to meet college expenses.

The problem doesn't say at which end of the month the money is withdrawn, but the timing makes a difference to the amount of interest earned, as shown in my image below by comparing the column D and E figures.

This interest difference can affect the month in which a zero balance is reached: eg, for withdrawals of $501 instead of $500, the column D algorithm reaches a zero balance in the month prior to column E's zero balance.


Btw, Excel has a handy function that calculates the number of periods (months, in this case) for the bank balance to reach zero. It gives the same answers as Hannibal's and Bob's algorithm (the same as my algorithm B) and also my algorithm A...which is comforting to know. smile

Enter the function into one cell for algorithm A and another cell for algorithm B. The respective solution for each algorithm will be displayed in whole + part months.

Here's a link to a very helpful MIF page: Compound Interest.

#2 Re: Help Me ! » Algebra 9 th grade » 2019-08-16 07:45:53

Hi ganesh;

There's an error in your -8x+3x calc...

#3 Re: Help Me ! » excel formula » 2019-08-14 09:08:35


I spent a bit of time trying find a solution that used the OP's requirements, but I failed and went back to what I had tried before with TEXTJOIN because I felt I'd got close then (sorry, Wood).

This time I think I succeeded (see image). The method returns column D results that are distinct, comma-delimited, and with each cell's contents sorted into descending per post #1's requirements.

Some comments:
   1. I used Excel's 'Sort Z to A' feature to sort each column D cell into descending order (don't know how to do it via formula).
   2. I haven't met post #10's requirements (don't know how).
   3. I populated column C via LARGE, with distinct values in descending order.


#4 Re: Help Me ! » excel formula » 2019-07-24 18:44:42

I'm sorry, Wood, but I know nearly nothing about arrays and {INDEX,MATCH,LARGE} formulas, and unfortunately I don't have enough time to research and learn this area.

I hope someone else here can help you (and maybe Bob knows how), but if not it may be best for you to try an Excel forum.

#5 Re: Help Me ! » excel formula » 2019-07-24 18:09:29

Hi Wood,

Could you please show us the best formulas you have tried.


#6 Re: Help Me ! » excel formula » 2019-07-24 10:38:31

Hi Bob & Wood,

Here's an image of my attempt, with formulas displayed in the lower section. I used some different values in column A than in your posts, just for testing purposes.

B1 contains the search value (5, in this case), which with my spreadsheet meant using an extra column (E). However, it enables changing the search value (if required) easily.

Column C returns all values <= the value in B1 ('5').

Column D gives the list of all unique Column C values (excluding blanks), in descending order.

The single cell E1 contains the comma-delimited output (in descending order) of the range D1:D4. Unfortunately I couldn't think of an automatic way to use TEXTJOIN that doesn't require having to select the cell range.



Hi Bob,

With my version of Excel, 'CONCATENATE' joins numbers and returns the result as a text string, so there's no need for column C's conversion to text.

You may already know this: CONCATENATE has an alternative 'ampersand operator' option, used like so:

#7 Re: Help Me ! » futoshiki » 2019-07-17 12:13:10

Hi Allerious,

The puzzle can be solved by logic, without any guessing.

Row 1 solves logically, as Bob said, and leads to multiple elimination of duplicates in the lower rows.

From there, eliminating the 2 from R3C2 ('R' = row, 'C' = column) leaves {3,4} in both R3C2 and R3C3, which enables us to eliminate the 3 from R3C1 and R3C4 because the 3 must be in either R3C2 or R3C3.

...etc, etc.

#8 Re: This is Cool » When is n(2n+1) a palindrome? » 2019-05-29 22:55:56

Hi Anthony,

Anthony Lahmann wrote:

The statement "0 is a palindrome" is ambiguous. That's why I excluded it.

Wikipedia includes zero as the first palindrome in its list here, as do OEIS here and Wolfram here.

#9 Re: This is Cool » When is n(2n+1) a palindrome? » 2019-05-29 16:26:41

Hi Anthony,

A computer program I ran found that 1331 ⇒ 3544453 is the next smallest palindromic pairing of n ⇒ n(2n+1) after your 66 ⇒ 8778.

It gave the following list as the first 12 such pairings:

0 ⇒ 0
1 ⇒ 3
5 ⇒ 55
9 ⇒ 171
66 ⇒ 8778
1331 ⇒ 3544453
123321 ⇒ 30416261403
1332222331 ⇒ 3549632679762369453
13322222331 ⇒ 354963215686512369453
123322223321 ⇒ 30416741529792514761403
133222222331 ⇒ 35496321045754012369453
1233222223321 ⇒ 3041674104186814014761403

#11 Re: Maths Is Fun - Suggestions and Comments » Minor Upgrade - may or may not go smoothly » 2019-05-15 23:08:22

bob bundy wrote:

Just a bobbym search with no keyword specified gives me this:

HTTP 500 error

I get the same error if I'm logged in, but when logged out I get access to 192 pages of 'Topics with posts by bobbym'!

#12 Re: Maths Is Fun - Suggestions and Comments » Minor Upgrade - may or may not go smoothly » 2019-05-15 21:30:32

bob bundy wrote:

The search function yielded no results for me...

Hi Bob,

Maybe you did something different from me, but my search for bobbym's posts containing the word 'pancakes' yielded these results:
- while logged in = 5, including 3 in Members Only (logged in example)
- while logged out = 2 (logged out example)

I used the plural to make sure of search success, given bobbym's penchant for pancakes (or so he led us to believe...not that I believe every word he said!) smile

My list of bobbym's topics is from 2009 to 2017: 257 topics when I'm logged in, and 240 when not. Members Only entries would account for that difference.

Looks like bobbym's first topic was 'chat possible?' on 22/4/2009, but it moved way up the list because of a 2017 post in it.

#13 Re: Maths Is Fun - Suggestions and Comments » Minor Upgrade - may or may not go smoothly » 2019-05-14 23:15:51

Hi zetafunc,

Yes, I miss bobbym immensely. Most of my >4500 posts were in conversations with him, and I thoroughly enjoyed my contact with him here. They were good days!

I think I've stumbled onto a workaround regarding your problem of not being able to view bobbym's posts: ie, try viewing them when not logged in. That works for me.

When I'm logged in I can't view bobbym's posts either, but I can view his topics and the posts in them. Links in those posts work too.

Maybe MIF can find a fix for this.

#14 Re: Help Me ! » [ASK] How to Read A'? » 2019-03-25 02:12:37

zetafunc wrote:

probably due to American influence.

Down here in Australia I haven't come across " ' " being read as "prime".

However, probably also due to American influence, "prime" is popular on English-spoken youtube videos featuring Rubik's cube solution algorithms, where " ' " placed immediately after the letter signifying a cube face denotes the anticlockwise (instead of the default clockwise) rotation of that face (eg, L', R', U', D' for left, right, up, down, respectively).

So for those examples, they say "left prime", "right prime", "up prime", "down prime".

#15 Re: Puzzles and Games » Unsolvable Master Detective game » 2019-03-17 14:26:37

Hi Alg Num Theory;

Sorry, but I rambled on in my three posts. I'll tidy things up into one post:

It appears that your puzzle has a glitch, because all constraints, other than the Labrador Retriever/Pyramid one that won't solve, are met...and the only possibilities I can think of whereby the puzzle could be sound are these two highly unlikely ones:

   1. A clue was moved from view.
   2. A given pre-solved square was converted into an unsolved state...which can be done by a single mouse click (either left, right or forward) while hovering the mouse over it (easy to do unknowingly). BUT, 'unsolving' a pre-solved square doesn't restore any of its pre-deleted matching elements, and so you'd have had to click on at least one of those to create multiple occurrences of that element.
      (a) In this scenario, and provided your other solutions are correct, a pre-solved dog, being the St Bernard or the Vizsla in either the first or third square in the dog row, leads to a solution.

But maybe the puzzle is sound, and the reason for the apparent glitch escapes me.

I'd be happy to check the puzzle by playing it from scratch...I just need you to tell me the pre-solved square/s in the original puzzle (the puzzle doesn't seem to be solvable without there being at least one of those).

Btw, I always take a screenshot before starting a game in case I need to restart.

#16 Re: Help Me ! » [ASK] Exponents and Roots » 2019-02-28 00:44:12

Ah yes, of course. up

I tried a few things in a brief attempt to work out how you got that answer, but didn't think of the missing parentheses.

#17 Re: Help Me ! » [ASK] Exponents and Roots » 2019-02-27 12:03:36

Hi Grantingriver,

I agree with what you said, but I tried Monox D. I-Fly's problem in my calculator, Excel and Mathematica and get approx -574.028.

My Mathematica formula is N[(7x-9/2Surd[y^5, 6])/((x^(5/6)-6y^(-1/3))x^-2)], and my calculator and Excel methods follow that line.

I can't think what I might have done wrong...

#18 Re: Help Me ! » Shortcut means to locate previous posts? » 2019-01-15 10:59:55

Hi EbenezerSon;

You can easily find all your posts by one of the following 2 methods.

Method 1:
- Log in, and click 'Profile' in the header bar near the top of the page.
- The Essentials page of the 'Profile menu' page should then display, but if it doesn't, click 'Essentials' in the menu on the left.
- Click 'Show all posts' in the 'User activity' panel that's near the bottom of the page.

Your posts will then be displayed, in descending date order, on the next page - 'Index » Search » Posts by EbenezerSon' - or over multiple pages if they don't all fit on 1 page.

The header bar above each post contains links to the respective forum, topic and post pages.

Method 2:
- Whether you are logged in or not, click on your 'live' name in the left-hand-side panel of any of your posts to access your profile page, and click 'Show all posts' in the 'User activity' panel.

- To find all your topics instead, just select 'Show all topics' in the final step of either method.

Other members:
- Method 2 can be used to find posts and topics of other members too, by clicking on their 'live' name in one of their posts.

I hope that clears it up for you. smile

#19 Re: Help Me ! » Letter-arranging » 2018-12-16 01:08:56


Thanks, Bob...I'll watch out for such!

Or are you playing 'Spot the Oxymoron'?

#20 Re: Help Me ! » Letter-arranging » 2018-12-11 12:41:41

Here's a solution (I think) using the permutations formula.

#21 Re: Help Me ! » Letter-arranging » 2018-12-10 21:02:51

And there I was thinking that you were just testing me to see if I'd notice you'd only done half the job! wink

I feel your pain, having lasted just one minute of listening to the Brexit news that I woke up to this morning (yes, we down here sometimes hear about overseas goings-on too). smile

#22 Re: Help Me ! » Letter-arranging » 2018-12-10 11:49:10

Hi Bob,

I like your strategy, but VCVCCV and VCCVCV are also valid arrangements because the constraint on adjacent letters only applies to vowels.

Those are the only other arrangements I could find.

That would double your answer, I think.

#23 Re: Coder's Corner » Complex Loop » 2018-11-21 00:52:03

Hi Zeeshan 01;

Zeeshan 01 wrote:

Any one can print this
*******   *******
******  *  ******
*****    *   *****   
****  *  *  *  ****
***        *     ***
**          *      **
*                     *

I thought I'd give your new puzzle a go, but unlike with your original puzzle, a simple solution has me stumped this time because it seems to lack symmetry now that you've added that internal cross. dunno It's trickier now...hence your change of the thread title from "Help in simple prob of loop" to "Complex Loop", I suppose.

Zeeshan 01 wrote:

Thanks for help but I need c language code

I still don't know c, nor the other two programming languages you mentioned (cpp and Java); but anyway, in case it helps someone, here's my effort in BASIC, based on my first solution to your original puzzle:

EDIT: It's closer to the second solution, actually.

    WHILE c>0
        IF c=7 THEN b$="   "
        IF c=6 THEN b$="  *  "
        IF c=5 THEN b$="    *   "
        IF c=4 THEN b$="  *  *  *  "
        IF c=3 THEN b$="        *     "
        IF c=2 THEN b$="          *      "
        IF c=1 THEN b$="                     "
        PRINT RIGHT$(a$,c)+b$+RIGHT$(a$,c)

My program's output:

*******   *******
******  *  ******
*****    *   *****
****  *  *  *  ****
***        *     ***
**          *      **
*                     *

#24 Re: Help Me ! » Number series » 2018-05-29 22:13:48

Sorry, but I don't understand that expression...too advanced for me.

What does your method suggest is the pattern for this sequence?

#25 Re: Help Me ! » Number series » 2018-05-28 18:34:24

Hi Alg Num Theory;

Well, that solution certainly wasn't staring me in the face! dizzy

I haven't got the first clue as to what it is or does or how it works, though, as it seems to be way beyond my low maths level (unless I've forgotten it from school).

I'll have to take your word for it that it's a solution. smile

EDIT: I entered it into W|A, which gave results (including this puzzle's solution) for the first 15 integer values of n. up

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