Question about bank interest

[Arka]

The article in the Editorial brought to mind a question that I have about bank interest.

How much daily interest (or, how much yearly interest) do we need to have so that the amount of daily interest increases by 3 NP a day?

Or, how many NP do we need in the bank account to have the daily interest increase by 3 NP a day?

[larph]

they said something about this in an editorial a while back. i was looking for it the other day too. if i find it (or if anyone else does) put it up here.

[Ange]

How about this? It's from this week's editorial. They give you the formula at the bottom. Hopefully, this is what you're looking for...just substitute the 3 from the million and compute.

This might have been asked before, but how many Neopoints do you have to have in the bank to get one million Neopoints of interest? ~__ultrastar__
Let's see… thanks to that nifty computer desktop calculator and rudimentary maths skills, it seems you need roughly 2,920,000,000 Neopoints. You'd better start saving now

WARNING: Educational content

To find out the answer to any similar question, just take the sum you want daily, multiply that by 365 (days in a year), then take the interest rate (in this case, 12.5% for the Ultimate Riches bank account), move the decimal point two spaces to the left, and divide to find out how much NP you'd need to save to get that daily interest amount. Voila!

1,000,000 x 365 = 365,000,000 / .125 = 2,920,000,000 NP!

[Arka]

How about this? It's from this week's editorial. They give you the formula at the bottom. Hopefully, this is what you're looking for...just substitute the 3 from the million and compute.

This might have been asked before, but how many Neopoints do you have to have in the bank to get one million Neopoints of interest? ~__ultrastar__
Let's see… thanks to that nifty computer desktop calculator and rudimentary maths skills, it seems you need roughly 2,920,000,000 Neopoints. You'd better start saving now

WARNING: Educational content

To find out the answer to any similar question, just take the sum you want daily, multiply that by 365 (days in a year), then take the interest rate (in this case, 12.5% for the Ultimate Riches bank account), move the decimal point two spaces to the left, and divide to find out how much NP you'd need to save to get that daily interest amount. Voila!

1,000,000 x 365 = 365,000,000 / .125 = 2,920,000,000 NP!

Thank you, Angisfab. I can't see how to make the formula answer my question, though. Unless perhaps X + 3 could be plugged in for the million, but it is beyond me. What I want to know is how many NP do I need so that the daily increase in the interest amount is 3 NP.

Larph, thank you for your response, too. I remember the question a few editorials ago- a few weeks (or months) ago-, but it still didn't answer my question. I think the question then was how many NP would you need to get a dailiy increase in interest of 5 NP. I could be mistaken about this, but I remember thinking at the time that I would like to know for a daily increase in interest of 3 NP. If the editorial did contain enough information to figure it out for 3 NP, either editorial actually, and someone could figure it out, I'd appreciate it.

[larph]

ha ho. nt issue 262. i'll post the q and a here. then i'll see if i can figure out the maths for your question or if someone else is smrter they can do so.

Hi TNT. I was wondering... assuming that you always upgrade your bank account to the highest possible setting to get maximum interest, how many NP would you need in your bank account, at a given interest rate, to raise the interest per day by 1 NP each day - by only collecting interest and not making NP in any other fashion? Say, if I had so and so many NP in my account and an interest rate of something, and I collected my daily interest of, say, 2000 NP or whatever, and the next day the daily interest would be 2001, next day 2002. What is the "lowest" account where this can work, assuming that you always upgrade your account as soon as this is possible, and how much NP would you need in that bank account? Just (really) curious. ~scaladenmark
*blinks* Erm, we decided to pass this question onto the amazing TNT member that does the Lenny Conundrum since he does like, maths and stuffs.

"Since the maximum interest rate is 12.5% per year, in order for the interest rate to go up one Neopoint, you need to earn (1 NP/day)*(365 days/year)/(0.125 per year) = 2920 Neopoints per day. In order to earn this amount, you need to have (2920 NP/day)*(365 days/year)/(0.125 per year) = 8,526,000 Neopoints in the bank.

However, that's less than the minimum 10,000,000 Neopoints required for the Ultimate Riches interest rate. So, the next one down is Neopian Mega-Riches, at 12% per year. Using the same methodology, you’d need [(1 NP/day)*(365 days/year)/(0.120 per year)] * (365 days/year)/(0.120 per year) which works out to 9,251,736 Neopoints!"

Well, there you have it! We'd double check his math, but our brains already exploded just reading the question. Medic!

The rest of us are better suited using these.

EDIT: ug. just reading it a few times hurts my head. i'll think about it later, but a quick (and probably wrong) response i think for 3np a day in interest increase would be 3(8,526,000) or 25,578,000? anyone have any clue if that's even close to good logic? or right?

[AySz88]

25,579,200 Neopoints, if you ignore rounding issues. You can run through the formula twice.

An increase of 3 NP of interest requires an increase of 8760 NP in deposits.
An increase of 8760 of deposits means 8760 interest => 25,579,200 deposited.

It's actually a lot less than that if you include the rounding up. A quick Excel guess-and-check gives me 20,144,022.

[larph]

thanks for that. (though sadly, you've put my u of c education to shame. i'm embarrassed)

[Arka]

Wow!

Thank you Larph and AySz88!

I see I have a very great amount to save if I ever want to see that. LOL!

[May]

Moved to Neopets Help


In the future, please post all questions such as this in the Neopets Help board.