Stupid Question

[Atlantic]

Sorry, it has been so long since i took math.

If you have a value (lets say 8000) decreasing by 13% every hour (13% of its actual value not the original value). What would be the formula to find out the current value after 5 hours.

 

Its like bonds. You invest money and it keeps increasing in accordance with the current value.

 

thanks in advance.

[fafalone]

n=Ce^kt

[Atlantic]

what are the variables?

 

Thanks

[hamzah]

I not sure what you mean by bonds, but with annual compound interest...to calculate how much you will have after a given number of years it is:

 

(original value) * (increase)^(number of years)

 

15% increase would be 115/100 = 1.15

 

an example would be:

£1000 in the bank...with a annual compound interest of 10%...how much is in the bank account after 3 years?

 

1000 * 1.1^3 = £1331

 

 

And in reply to your problem:

 

Sorry, it has been so long since i took math.

If you have a value (lets say 8000) decreasing by 13% every hour (13% of its actual value not the original value). What would be the formula to find out the current value after 5 hours.

 

it would be:

 

(initial value) * (decrease)^(number of hours)

 

8000 * (0.87)^5

[xXxAuroraxXx]

y = 8000(1 - .13)^5

 

y = 8000(.87)^5

 

y = 8000(.498)

 

y = 3987.86

 

Im not sure if "y" is the correct variable...

 

If you wanted to see increase

 

y = 8000(1 + .13)^5

 

I think.

[Dave]

That's right. In general, for things like these interest values, you can use the formula:

 

y = x*(interest)^n to calculate the value of x after n iterations of applying interest or whatever to it. Note that this only works for values of n which are in the natural (counting) numbers - it doesn't work for n = 12.32 for example, for that you need faf's equation.