sort of a random question but...

[jakecubee]

I was just wondering, how much intrest per day would you have to get so everytime, the intrest goes up?

[crashbash]

it depends on the amount in your account and the type of account you have. right now I make 10.5% interest yearly, and the daily is 509nps if I collect, you can't collect more than what your account allows, but you can nps to it to make the interest go up, although I don't know how much it would be. I don't even know how much I have to put in my account to make the interest go up. But if you're good at math then it's really easy to figure out when the daily interest goes up based on how much is being paid daily and how much you have and how much interest (%) is on your account, and then dividing by 365. I used to work for a car dealership so I know how interest is figured out, I just can't do the figures myself.

[farside]

I was just wondering, how much intrest per day would you have to get so everytime, the intrest goes up?

Interesting question. Let's see.

The Neopets interest equation goes like this:

d = (i x P) / 365

where d is the daily interest, i is the current interest rate, P is the principle, and 365 is the assumed number of days per year. We can also write this as:

d = (i / 365) (P)

For the interest to change every day, assuming the interest rate remained the same, you want:

d2 - d1 = 1

where d2 is the daily interest for a given day and d1 was the daily interest for the day before. 1 is the minimum possible increase in daily interest, since Neopets doesn't use decimals, so we want to check when the change in daily interest caused by d1 to be at least 1.

d2 = (i / 365) (P + d1), and
d1 = (i / 365) (P)

so,

d2 - d1 = 1 becomes

[(i / 365) (P + d1)] - [(i / 365) (P)] = 1, or, factoring out the (i / 365),

(i / 365) (P + d1 - P) = 1, simplifying,

(i / 365) (d1) = 1

Isolating d1,

d1 = 1 / (i / 365), or

d1 = 365 / i

So, if your current interest rate is 10.5%, it is calculated as follows:

d1 = 365 / 10.5% = 365 / 0.105 = 3,476.19 or rounded up 3,477

In other words, if your current interest rate is 10.5%, your daily interest would have to be at least 3,477 NP to cause the next day's daily interest to be at least 1 NP more. But, if your principle is large enough to get that much daily interest, your account should be eligible for an interest rate higher than 10.5%.

[Troggy7]

AHH MATH!!! BACK DEMOND

xDD

I make

11.0% per year
722 NP per day

Dunno if that helps

[jakecubee]

well i am at 11% and make 1027np a day, when i collected my interest at 1023np it didnt do anything

[farside]

well i am at 11% and make 1027np a day, when i collected my interest at 1023np it didnt do anything

Based on the equation, at 11% interest rate, you would need to add

365 / 11% = 365 / 0.11 = 3,318.18

or 3,319 NP to your bank account to squeeze an additional 1NP of interest the next day. Try playing some games and adding another 2,292 NP to your bank account. You should see the daily interest change then.

By the way, an easier way to derive the same equation would have been to ask what additional amount of principle (which we'll call deltaP) would be required to get 1 NP of interest. From the Neopets interest equation:

d = (i / 365) (P),

plugging in values,

1 = (i / 365) (deltaP),

and then solve for deltaP,

deltaP = 1 / (i / 365), or

deltaP = 365 / i

[JhasNeeh]

Yay, simple Maths made into a degree standard.

I think the highest interest rate is 12%, and at this rate you need 3041.7 nps to add 1 np to your daily interest.

This is very easy to work out, if you know how the interest is worked out int the first place, all you have to do is reverse things. IE.

To work out the daily interest (d): NPs in bank (N) multiplied by the interest rate (i) divided by the days in a year (365).

OR: (Nxi)/365=d

All you have to to workout how much would take you up a NP is turn the order the letters are around, and class d as 1 (so you find out how much takes you up). IE.

(dx365)/i=N

At 12% this works out to be 3041.7. Ta-da.

And just for those who, like me, long for the day when the interest alone will bump it up, just plug that number (rounded up) is as d and you will find thus:

(3042x365)/0.12=9,252,750.

I'm only 6 Million off.