Abag has 16 blue, 20 red, and 24 green marbles. what fraction of the marbles in the bag are blue?

You have to add all of the number together and then you put the number of blue marbles over the sum of all the marbles which gives you

16/60 then you have to put it into a smaller fraction by dividing the top and bottom by the same number
you can divide both by 4 which gives you

4/15 is the fraction of marbles in the bag that are blue.