How to calculate a progressive %

[giulio2010]

Hi, guys
I am looking for a trick to calculate a progressive %.
I went to the bank last week but no1 there knew how to do it so I am wondering if there is anyone here who knows better then people employed by the bank...
I write down an example if I did not explain well my self:
day 1) £200 x 20% = £240
day 2) £240 x 20% = £288
day 3) £288 x 20% = £345,6
How much will I earn by day 30 or day 365...Is there a single math which provide me a result without calculating day by day..
Thank you in advance..

[CaerMyrddin]

200x(1,20)^n, where n is the number of days.

[freddy]

just do it in excel

put your starting bank in Cell A1 and then copy this formula in to a2 and then copy down the required number of times.

=SUM(A1)*1.2
=SUM(A2)*1.2
=SUM(A3)*1.2

etc

[giulio2010]

Thank you..

200x(1,20)^n, where n is the number of days.

Thank you..

just do it in excel

put your starting bank in Cell A1 and then copy this formula in to a2 and then copy down the required number of times.

=SUM(A1)*1.2
=SUM(A2)*1.2
=SUM(A3)*1.2

etc

That was exactly what I was looking for...thank you both again...

I can't wait to go to my Bank and make fun of them...hehe

[Akindwurd]

It's called compound interest, by the way. Presumably your bank will know it as "interesse composto".

[giulio2010]

It's called compound interest, by the way. Presumably your bank will know it as "interesse composto".

I have done a bit more of research after this post..Thanks to you guys I know how it works and how it's called..
Interesse composto it's the 1st question I will ask next time I go to my bank branch...However even a friend of mine which works in bank did not know...Makes you wonder how this people get hired..big tits help