Okay, first just think about the mass in the left hand side.
We know it is in equilibrium, therefore all forces have to be balanced.
Now let's think what those forces are. Obviously the mass experiences the downwards pull of it's weight (W = mg), and it will also experience and upwards pull from the wire.
If we define up to be positive, and remember that all forces are balanced, we get the equation:
T - W = 0
T = W
T = mg
m = 2.0, g = 9.81
Therefore T = 2.0 * 9.81