Correct option is A)

Let x be the weights, in Kilograms, of pure water to be added. Let y be the weight, in Kilograms, of the 10% solution.

Hence x+100=y

Let us now express the fact that the amount of salt in the pure water (which is 0) plus the amount of salt in the 30% solution is equal to the amount of salt in the final saline solution at 10%.

0 + 30% 100 = 10%y

Now by substituting the value of y in terms of x, we get the equation as,

30% 100 = 10%(x+100)

30×100=10(x+100)

3000=10x+1000

10x=2000

x=200

Answer x=200 Kilograms.