im suffering http://prntscr.com/ijd8zm

Question

Shadow · Answer

Hello @fairy Do you know how to approach this problem?

fairy · Answer

ye kinda

Shadow · Answer

And what does that approach consist of?

fairy · Answer

well so far i got 1400(1+0.085) is that right?

Shadow · Answer

You are using the "Simple Interest" formula which works when you're dealing with interest calculated only once per year. Here we have it being calculated multiple times.

Shadow · Answer

That looks like:

$$A(t) = P(1 + r) ^t$$

Which means account balance over t years is equal to the principal (initial) amount multiplied by 1 + the rate by t years.

fairy · Answer

errr in the example it looked rlly different

Shadow · Answer

What example?

fairy · Answer

http://prntscr.com/ijdejr

dude · Answer

Shadow was following your example, the difference was that your sample was decay in which you had to subtract 1 meanwhile this question involves growth

dude · Answer

$f(t)=1400(1+0.085)^{\large{\frac{t}{3}}}$

Shadow · Answer

Sorry, getting ready for a gathering. @dude has you