How much water must be added to 20 L of 30% salt solution to make it 20%?

Question: How much water must be added to 20 L of 30% salt solution to make it 20%?

Solution:
Total solution 20 L
30% salt solution has salt of = (20×30)/100 = 6 L

Now,
Let the amount of water to be added to make 20% salt solution = x liters
Then, new total solution = 20 + x
Salt remains = 6 L

New salt percentage =
→ 400+ 20x= 600
→ 20x= 200
→ x= 10