Calculating Voltage Across a Capacitor

[roam]

Homework Statement

[PLAIN]http://img189.imageshack.us/img189/4555/capacitorh.jpg

Homework Equations

I(t)=I_0 e^{-t/\tau} (current as a function of time for a capacitor being charged)

The Attempt at a Solution

The time constant of the circuit is τ=RC=7s. And the initial current in the circuit is

v/R_eq=300/1489=0.2A (I know this is correct)

Now pluging into the equation:

I(5)=0.2 e^{-5/7}=0.0979 \ A

V=IR= 0.0979 \ A \times 1489 \Omega = 145.73 \ V

But the correct solution must be 153V. I'm very confused, what's wrong with my working?

 

[ehild]

Is V=IR the voltage across a capacitor? ehild