Answer:
Step-by-step explanation:
First Group like terms:

Add similar elements:




A is the correct answer I hope that helps :)
There are 18 students in Grade 7, 10 are in band, so 10/18 = 0.56 are in band.
There are 12 students in Grade 8, 10 are in band, so 10/12 = 0.83 are in band.
Students in Grade 8 are more likely to be members of the band.