Capacitor problems

A 12µF capacitor is connected by a switch to a 100 volt DC
supply via a 20Ω resistor. Assume the capacitor is initially
uncharged. Calculate:

a.      The TIME constant

b.      The INITIAL current at the moment of closing the switch

c.       The TIME for the current to fall to 3 amps

d.      The TIME for the voltage of the fully charged capacitor to fall to 70 volts. (The
capacitor is discharged through a 20 Ω resistor)

e.       Sketch the growth of voltage across the capacitor against time