Finding the Time Constant in a circuit

[mlb2358]

Homework Statement

Find the time constant in the following circuit when switch K1 is open.

R1 = 100 Ohms
R2 = 200 Ohms
C1 = 6 micro Farads
E1 = 9V

Homework Equations

T = RC

The Attempt at a Solution

When the resistors are in series or parallel, I am clear on how to do this, however when the capacitor is discharging, I don't think the resistors are in series or parallel, so I don't know how to find the equivalent resistance.

 

[gneill]

Is the diagram correct? What is that wire that runs from where the switch and R1 meet down to the bottom node? Doesn't it prevent the switch and voltage source from affecting the rest of the circuit?