Problem set 1 Q5

I assume that you meant Q5a in the problem set #2 (not #1). If yes, you are a bit ahead of us, but nevertheless, here is the answer on how to calculate gravimetric water content (as asked in Q5a of problem set #2):
gravimetric water content = mass of water/mass of oven-dried soil
One determines mass of water in soil by drying soil samples in the oven, and that info is mentioned (ie given) in this question.