First, find the area of the hallway.
\(Area=length*width\)
\(A=90*7\)
\(A=630\)
Now you know there are 630 square feet to be cleaned. To find the amount of cleaning solution needed, multiply this number by 1/2.
\(Solution=area* \frac{1}{2}\)
\(S=630* \frac{1}{2}\)
\(S= \frac{630}{2}\)
\(S=315\)
Answer: 315 fluid ounces