Conversion from gallons to quarts
1 gallon = 4 quarts
Now,
Angela has

gallons =

= 10 quarts of blue paint
Ryou has 1/2 of what Angela has = 1/2*10 = 5 quarts of white paint.
Each wall requires

of paint.
After coloring;
Blue colored walls = (10)/(

) = 3 walls with 7/11 quarts of paint remaining.
White colored walls = (5)/(

) = 1 wall with 9/11 quarts of paint remaining