The combined width would be adding the two widths together.
3 1/4 + 3 2/3
Fist convert each number into an improper fraction, find a common denominator , add them together then convert back to a proper fraction.
3 1/4 = 13/4
3 2/3 = 11/3
13/4 + 11/3
Common denominator of 3 and 4 = 12
13/4 = 39/12
11/3 = 44/12
39/12 + 44/12 = 83/12
Now convert back to a proper fraction:
83/12 = 6 11/12, which can be rounded up to 7 feet.
The answer is D.