This happens when Ruby becomes disappointed with Tom when the hose leaks and Ruby can no longer dive. The two stop hanging out, and Tom loses her friendship.
The light, then, is the light that her friendship brought to his life. Her friendship is light -- it is happiness and is joy to Tom. When the two friends stop hanging out, the light goes out of the marsh. The author is saying the joy has gone out of Tom's life.
This isn't an English Question but...
What you do first is find the LCD (Least Common Denominator)
You do this by finding the factors of 16 and seeing if they correspond with two.
So you're factors are, (1,16) (2,8) (4,4)
So the LCD is 2. You would then make each fraction over two. Since 1/2 is already over 2 you would make 5/16 over two by dividing by 8.
That gives you .347 or 347/1000
Then you would add each whole number, 24 + 2. This gives you 26 and then add the decimel. 26.347
There is probably a simpler way but here's mine.
The first option would be the most reasonable one
