Problema Solution
A scientist wants to dilute a 60% acid solution by adding some 20% solution. If she starts with 80 ml of the 60% solution, how many milliliters of the 20% solution does she need to add to get a resulting 45% acid solution?
Answer provided by our tutors
let 'x' represent the amount in ml of 20% solution added, then the new volume of the solution is 'x+80' ml
concentration = pure-acid/total volume
so the new concentration is formulated as follows:
0.45 = (0.6(80) + 0.2(x))/(x+80)
solving for 'x' we have x=48
the scientist should add 48 ml of the 20% solution