Answer:
10 kg
Step-by-step explanation:
In 3% concentration of 20 kg of seawater, there will be kg of salt.
So, if it is a 2% solution of seawater,
Then 2 kg salt will be there in 100 kg solution.
So, 0.6 kg salt will be there in kg of solution.
So, to make a solution from 3% to 2% we have to add (30 - 20) = 10 kg of water with a 20 kg solution. (Answer)