We have all the information we need to answer this one with ease. It tells us how much downward force the anchor has - 22 Kgs and how much upward force the displacement is causing - 18 litres, and which type of water the anchor lying in.
Since it's asking for an answer to be expressed as volume we must convert the weight from Kgs to litres, since this is seawater that will be 22/1.03 - the weight of the object divided by the weight of the water. That equals 21.36 litres.
That represents the total volume required to lift the anchor. Since I already have 18litres of displacement already assisting this, I have to subtract that from the total amount. 22.36-18=3.36 litres.
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