The room is a rectangle with dimensions 25 and x + 10. The area of a rectangle is the product of its dimensions, so the area will be:
We have to add the parenthesis because we first need to add 10 and x and then multiply. Distributing the 25, we have:
As we can see, this matches what Ron thinks the area will be, so he is correct. Thus, the answer is "Yes". The why can be both because the area is the sum of 25*10 and 25x and because the area is the product of 25 and 10 + x.
So, the correct alternatives are A and D.