How long will it take to double an amount invested at 8% compunded quarterly?

Question

anonymous · Answer

I mean 9% ..
sorry.

anonymous · Answer

A=P(1+0.08/4)^4

anonymous · Answer

That's the answer???

anonymous · Answer

you have a number for plug  in?

anonymous · Answer

P for principlal money you deposit

anonymous · Answer

I'm trying to find P??? I don't have any more numbers..

anonymous · Answer

sorry you said 9%

anonymous · Answer

if you don have number for P think teacher only need the equation, not the answer number

anonymous · Answer

A=P(1+0.09/4)^4
that all

anonymous · Answer

if you have A (total ) you can find pricipal amout, or you have principal amout ,you can find the total

anonymous · Answer

So it's 1.009030421?

anonymous · Answer

how you get this number 1.009030421?

anonymous · Answer

From 
(1+0.09/4)^4

anonymous · Answer

you should check it you missing one more number?

anonymous · Answer

I am not. That's the given problem.

anonymous · Answer

I missing you said double 
2A =P (1+0.09/4)^4
but still not enough information,you may repost question again to see some one have differen answer