Final answer:
Jen needs to add 12 grams of water to 18 grams of salt to create a 60% salt solution, as 60% of the total solution's mass must be salt.
Step-by-step explanation:
To make a 60% salt solution, Jen will need to calculate the total mass of the solution and then determine how much water to add to her 18 g of salt.
A 60% solution means that 60% of the total mass of the solution is salt. If s represents the total mass of the solution, we can write this as: (18 g / s) * 100% = 60%. Solving for s, we find that s equals 30 g, which is the total mass of the salt solution needed.
To find the mass of water required, subtract the mass of salt from the total mass of the solution. Therefore, Jen needs to add 30 g - 18 g = 12 g of water to her 18 g of salt to create the desired solution.