A pharmacist has 80 milliliters of a 25% saline solution. which expression can be used to find the percentage concentration of the final solution if she adds x milliliters of a 10% saline solution?

Final concentration % = [grams of salt / mililiters of solution] * 100

grams of salt = grams of salt from solution 1 + grams of salt from solution 2

grams of salt from solution 1 = mililiters * %/100 = 80 mililiters * 0.25 g/mililiters = 20 g

grams of salt from solution 2 = mililiters * %/100 = x*0.10 g/mililiters = 0.1x

mililiters of final solution = mililiters from solution 1 + mililiters from solution 2

mililiters of final solution = 80 mililiters + x mililiters

=> Final concentration, % = [0,10x + 20 g] / [x + 80 mililiters] * 100