It is 350% I think, because you are trying to find how many groups of 2 go into 7. So, you have to divide 7 by 2. You get 3.5. 3.5 in percentage form is 350%
To factor, we always have to look for common factors in the numbers given to us. In this case, in 1/2 and 6, the common factor is 1/2. Therefore, we will have to factor like so:
1/2d + 6 = 1/2 (d + 3)
Hope this helps!
The distance between the windows is not given. I have searched for this question in other sources and came up with 6.5 ft.
6.5 ft = 78 inches
The width of the bookshelf = 77 inches
Hence the book shelf with fit between the windows and still there will be 78-77 = 1 inch of space remaining
Hence the right option is option C