First turn 1/2 to 2/4 so you have a common denominator.
Next turn the mixed numbers into improper fractions:
11 3/4 --> 47/4 and 8 2/4 --> 34/4
Subtract:
47/4 - 34/4 = 13/4
Divide:
13/4 = 3.25
3.25/2 --> 1.625 or 1 5/8
Therefore, he will have to place it 1 5/8 feet from each side
Hope this helps!
