Conversion from gallons to quarts
1 gallon = 4 quarts
Now,
Angela has [tex]2 \frac{1}{2} [/tex] gallons = [tex] 2\frac{1}{2} *4[/tex] = 10 quarts of blue paint
Ryou has 1/2 of what Angela has = 1/2*10 = 5 quarts of white paint.
Each wall requires [tex]2 \frac{3}{4} [/tex] of paint.
After coloring;
Blue colored walls = (10)/([tex]2 \frac{3}{4} [/tex]) = 3 walls with 7/11 quarts of paint remaining.
White colored walls = (5)/([tex]2 \frac{3}{4} [/tex]) = 1 wall with 9/11 quarts of paint remaining