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:
[tex]4 / (100 + x) + 0.08x / (100 + x) = 0.06[/tex] [Multiplying by (100 + x)]
[tex]4 + 0.08x = 6 + 0.06x[/tex] [Transposing terms]
[tex]0.08x - 0.06x = 6 - 4[/tex] [ operating]
[tex]0.02x = 2[/tex] [Dividing by 0.02]
[tex]x=100[/tex]