A 60 F capacitor that had been charged to 30 V is discharged through a resistor.

A 60 µF capacitor that had been charged to 30 V is discharged through a resistor. The capacitor voltage as a function of time is shown in the figure below, in which each interval on the horizontal axis equals 0.1 ms. What is the value of the resistance?
http://www.webassign.net/knight/p31-73alt.gif