3.5 gm of solid Barium fluoride is added to water forming 1 lit of solution at 25°C. Solubility product of salt is 4 × 10–6. What will be the minimum volume of water to be added to above solution to dissolve the salt completely. (At. wt. Ba : 137, F : 19)

The solubility of a salt at different temperatures is tabulated below:
$$\begin{array}{cccccc}\text{Temperature (degree celsius)}& \text{20}& \text{30}& \text{40}& \text{50}& \text{60}\\ \text{Solubility (g per 100 ml)}& \text{34.2}& \text{37.2}& \text{40.1}& \text{42.6}& \text{45.8}\end{array}$$

Deepti takes 50 ml of water and adds 20 g of salt to it. The temperature of the solution is ${20}^{\circ }$C. Choose the correct statement.

How much water should be added to 15g of salt to obtain 15%salt solution?

How much water should be added to 15grams of salt to obtain 15% of salt solution?