Find the value of a capacitor given percent of the initial value

[rocapp]

Homework Statement

A capacitor is discharged through an 80.0 ohm resistor. The discharge current decreases to 23.0% of its initial value in 1.50ms .

What is the value of the capacitor?

Homework Equations

t=RC

The Attempt at a Solution

1500 μs = 0.23 RC
RC= 6521.74

C= 6521.74/R

C= 6521.74/80 = 81.5 μF


This is not correct... Please help! It's due within the next thirty minutes!

 

[Simon Bridge]

The voltage vs time graph is not linear.
$$v(t)=V_0e^{-t/RC}$$