Hi Gabby,
Let x = number of oz of dandelion root needed.
ING # oz • conc =
DR x • .12 = .12x
S 30 • .54 = 16.2
N-M (x + 30) • .30 = .30(x + 30)
.12x +(.54 x 30) = .30(x + 30)
x = 40 oz
Regards,
Anita A.