Answer:
$120
Step-by-step explanation:
The sixth grade band members has a total of sixteen members, as the problem says that fifteen have sold a certain amount, and how much will the LAST student have to sell.
As the mean is $60 per student, and we have 16 students, the total raised need to be 60*16 = $960
The first fifteen students have earned $840, so to reach $960, the last student will have to raise 960 - 840 = $120, so the mean will be $60 per student.
