To find the average, we need to add all the data together and then divide by the number of entries on the set (in this case 4).
To add fractions we have to find a common denominator. First we end to make sure all the fractions are reduced as far as possible.
6/24 can be reduced to 1/4.
Now we have denominators of 4, 5, and 10 to work with. All of those are factors of 20 so we will use that as the common denominator. Remember we reduced 6/24 to 1/4.
