Answer:the number of sixth graders is 28
Explanation:
Total number of students in the school band is 70. 40% are sixth graders. 20% are seventh graders and the rest are eighth graders. This means that the percentage of eighth graders is 100 - (40+20) = 100 - 60 = 40%
This means that the number of sixth graders would be 40% of the total number of students in the school band. It becomes
40/100 × 70 = 0.4×70 = 28