What is the volume, in cm cubed, of 2.0 LBS of mercury? Density of mercury = 13.6 g/cm cubed.

First you need to convert 2 lbs to kg of mercury using:
1lb =0.4536kg according to Google.

That makes 0.91 kg of mercury.
Then convert kg to g by multiplying by 1000.
Then divide by the density to end up with your volume.

Should end up with 67 cm^3