Julia has 4 gallons 2 quarts of water. ally needs the same amount of water but only has 12 quarts. how much more water does ally need?

Ok so what do we know :
 
4 quarts = 1 gal
Julia has 4gal and 2 quarts or 18 quarts
ally has 12 quarts

so if julia has 18 quarts and ally has 12 that means that ally needs 6 more quarts (or 1gal 2 quarts) so that she and julia can have the same amount

Julia has:  (4 gal)*(4 qt/gal) + (2 qt) = 18 qt
Ally has:  (12 qt) = 12 qt

(Julia) - (Ally) = (18 qt) - (12 qt) = 6 qt

Thus, Ally needs 6 more quarts