Question

8000 deposited at 5% compounded quarterly to reach atleast 16000

Answer 1

@myininaya @amistre64

Answer 2

@Zarkon

Answer 3

well, we start with a balance of 0, and add payments quarterly

or, we could just start with a payment as the balance

\[B_n=Pk^n+P\frac{k^n-1}{k-1}\]

and solve for n

Answer 4

isnt 8000 * 2 = 16000?

just wondering

Answer 5

so thats what, 3 months?

Answer 6

\[16000=8000(1+\frac{k^n-1}{k-1})\]
\[2=1+\frac{k^n-1}{k-1}\]
\[1=\frac{k^n-1}{k-1}\]
\[k-1=k^n-1\]
\[k=k^n\]
\[n=1\]
so, 1 compounding period is a quarter of a year