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?
a. y= (0.25(80)+0.1x)/x .100
b. y= (0.25(80)+0.1x)/80 .100
c. y= (0.25(80)+0.1x)/80+0.1x ·100
d. y= (0.25(80)+0.1x)/80+x · 100