The greatest number of groups that can be formed is 7.
It should be noted that there are 56 dancers wearing green outfits and 42 dancers wearing yellow outfits.
The greatest number of groups that can be formed will the highest common factor between the numbers.
It should be noted that the highest common factor between 42 and 56 is 7.
Therefore, the greatest number of groups that can be formed is 7.
Learn more about factor on:
brainly.com/question/24673551
#SPJ1