Answer:
0.16 liters of water
Explanation:
Samantha's recipe makes 0.06 liters of solution. She wants 0.48 liters of solution, an amount 0.48/0.06 = 8 times as great as made by one recipe.
The recipe calls for 0.02 liters of water. To make 8 times the amount of solution, Samantha will use 8 times as much water: 0.16 liters.
Samantha will use 0.16 liters of water to make 0.48 liters of solution.
__
Alternate solution
The fraction of solution that is water is (0.02 L)/(0.06 L) = 1/3. For 0.48 L of solution, the water needed is 1/3×0.48 L = 0.16 liters.