Answer:
14 %  pure juice comes from  first brand
Step-by-step explanation:
Mixture:
17 gal 30% contains: Â 17x 30% = 5.10 gal pure juice
 Second brand:
8 gal 48% contains: Â 8x40% = Â 3.84 Â gal pure juice
5.10 − 3.84 = 1.26  gal
1.26  gal is  coming  from 9 gal of first  brand
The percentage of first brand  is:
(1.26/9) x100 Â = Â 14 % Â pure juice.