Answer:
8
Step-by-step explanation:
We use the equation for the percentage of solute concentration in a solution:
(1)
In this case the equiation (1) is transformed into:
(2)
n = number of times he must waves his wand to have a solution that is at least 34% DeMuggle juice.
Vpo = Initial volume of the magic potion = 2000ml
Vjo= Initial volume of DeMuggle juice = 30% * Vpo = (0.3)2000 = 600ml
Vb= Volume of a bottle = 25ml
Vjb = DeMuggle juice volume in a bottle = 75% * Vb = (0.75)25= 18.75ml
Vpmt = Total volume of the magic potion = 2000 + 25*n = Vpo + Vb * n
Vjt = Total volume of DeMuggle juice = 600 + 18.75*n = Vjo + Vjb * n
Replacing in (2):
Since the number of times the wand should be waved must be an integer, it approximates 8
Replacing n=8 in (1)