Problema Solution
a pharmacist wishes to mix a solution that is 4% minoxidil. She has on hand 80ml of a 1% solution and wishes to add some 6% solution to obtain the desired 4% solution. How much 6% solution should she add?
Answer provided by our tutors
concentration = pure minoxidil / total volume
we desire a 4% solution and start with 80ml of a 1% solution, so we start with this much pure minoxil:
80 * 0.01 = 0.8
let 'v' represent the amount of 6% solution added:
0.04 = (v+0.8)/(v+80)
solving for 'v' we have v=2.5
2.5ml of the 6% solution should be added
concentration = pure minoxidil / total volume
we desire a 4% solution and start with 80ml of a 1% solution, so we start with this much pure minoxil:
80 * 0.01 = 0.8
let 'v' represent the amount of 6% solution added:
0.04 = (0.06v+0.8)/(v+80)
solving for 'v' we have v=120
120ml of the 6% solution should be added