Question

at a gymnastics competition, joey scored 9.4,9.7,9.9,9.8. carlos scored 9.5,9.2,9.7,9.7. who had the greater average score? by how many points was his score greater?

Answer 1

You have an answer so ill just tell you how to di it (assuming you didn't know)
you would add all the numbers in the set 9.4,9.7,9.9,9.8. (joey) and get 64. since there are 8 numbers in  the set you would divide your total (64) by 8 to get 8 as your average. same rules apply to carlos. 

Answer 2

Joey has an average of 8. While Carlos has an average of 7.125. Joey has the greater average by 0.875