Question

A Pharmacist whishes to mix a solution that is 6% Minoxidil. She has on hand 100 ml of 4% solution and wishes to add some 8% solution to obtain the desired 6% solution. How much 8% solution should she add?

Answer 1

Answer:

100

Step-by-step explanation:

Let x be the amount to be added of the second solution. For every 100ml of it 8 units of minoxidil are added. The total amount of solution will be (100 + x), so the final concentration is given by:

$4 / (100 + x) + 0.08x / (100 + x) = 0.06$  [Multiplying by (100 + x)]

$4 + 0.08x = 6 + 0.06x$                            [Transposing terms]

$0.08x - 0.06x = 6 - 4$                              [ operating]

$0.02x = 2$                                                 [Dividing by 0.02]

$x=100$