The first one is 4/10000
the second one is 0.0984
I think you meant to say n = 11. If so, then you are correct and it leads to the proper length for FG, which is 16 units. Nice work.
A.1:5 because 3 came first and
3:15
3÷3=1
15÷3=5
Therefore the answer is =1:5
My father taught me a method that I call, 'throwing some thing over the wall'. There is a sample equation for the first picture that shows you how it works. It's a great way to help isolate the variable and I hope that it works for you. The second picture contains the answers I got through the use of this method. I'm sorry for the messy handwriting; I was on a bus.