Final answer:
Sean and Sandra painted a combined total of 7/12 of the fence, so 5/12 of the fence remains unpainted.
Step-by-step explanation:
The question is asking us to calculate the remaining portion of a fence that has not been painted after Sean and Sandra have painted their parts. Sean has painted 1/3 of the fence, and Sandra painted 1/4 of the fence. To determine the unpainted portion, we need to add the fractions representing the painted parts and subtract that sum from the whole.
First, let's find a common denominator which is 12 in this case. Sean's portion becomes 4/12 and Sandra's portion becomes 3/12. Adding Sean's and Sandra's portions gives us 7/12.
Now, subtract the painted portion from the whole, which represents 1 or 12/12.
1 (12/12) - 7/12 = 5/12
Thus, 5/12 of the fence remains to be painted.