Let x represent the amount that Fred gets for his allowance weekly.
Fred spent half his allowance on the movies. This means that the total amount that he spent on the movies is x/2. The amount that he is left with would be
x - x/2 = x/2
He washed the family car for six dollars. This means that the total amount that he is left with would be
Where 1/3 of the 1 section had been painted, have each section have 3 parts. So each complete section will be 3/3. Where there is 4 section with 3 parts each, we have 12 parts. Thus, you painted 1/12 of the fence.