The answer is C. I think you have to start with a negative.
Answer:

Step-by-step explanation:
Let:

This allows us to manipulate the equations like we normally would.

Then, we return the values where they belong.

Finally, we add:

By adding all sides of the rooms walls you get 64 feet for your perimeter 20+20+12+12=64 feet
Given a series, the ratio test implies finding the following limit:

If r<1 then the series converges, if r>1 the series diverges and if r=1 the test is inconclusive and we can't assure if the series converges or diverges. So let's see the terms in this limit:

Then the limit is:

We can simplify the expressions inside the absolute value:

Since none of the terms inside the absolute value can be negative we can write this with out it:

Now let's re-writte n/(n+1):

Then the limit we have to find is:

Note that the limit of 1/n when n tends to infinite is 0 so we get:

So from the test ratio r=0.4 and the series converges. Then the answer is the second option.
Width: 1/4 Explanation: First you set up the problem as 1/16 divided by 1/4, then you change the division sign to multiplication and then you flip the second fraction which is 1/4, you should have 4/1, next you have a problem like 1/16 x 4/1 1x4= 4 and 16x1=16, did you get 1/4 as your product? If you didn’t, repeat the steps and try as many times until you get it, it is the only way to learn. Thank you for asking this question and have a great Evening! :)